VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc 216 Carburetor Problem

I have a 1940 1/2 ton pickup that is stock except that it has a 1948 Chev passenger car cylinder block with a 1940 head and a Carter W-1 carburetor. The engine runs great, but once it is fully warmed up, as after a few miles on the highway, when I shut it down for 10 or 15 minutes to go into a store, for instance, when I try to re-start, the engine is flooded and takes a great deal of extra cranking to draw in enough air to dilute the gas that has spilled into the manifold while sitting.

It seems to me that perhaps the float valve is leaking, allowing the level in the float chamber to get too high. When running, it doesn't seem to matter, but when shut down, the high level results in gas overflowing the "slip nozzle" into the carburetor throat. I've set the float level slightly lower than called for and checked the float valve by blowing into the carburetor gas inlet. The valve seems to shut tight.

Is there another common problem I am overlooking that might cause my flooding problem?

Mark Yeamans
VCCA #35724

Press the accelerator pedal slowly all the way down to the floor. Now try to start the engine and see if that makes a difference.

Another way to look at is that the fuel is perking out of the carb while sitting and your excessive cranking is providing fuel to refill the carb. If the starter is in good condition and you have proper sized cables with a strong battery then the fuel is the problem. Personally I have found that after the car sits and it is time to restart I depress the gas pedal 1/2 way then try to start. If fuel evaporation is the problem depressing the pedal shoots fresh fuel into the manifold and allows fresh air in as well. You can do this about twice before flooding the engine and then you must floor the pedal and hold it there while cranking to clean out the cylinders.

Check the needle in the float circuit. If it is a Viton tipped needle throw it away and replace with a metal needle. Install a matching seat for the metal needle as well.

Dog is a Viton tipped needle one that has a red-sh tip or what dose it look like

The Viton needle has a rubber tip.

OK THANK YOU

Mark,
I assume that the heat riser is not stuck in the heat position.
Next time disconnect the gas line as soon as you pull into your drive way and then watch if the fuel spills over. If it does it cased by expansion of the gas. If not a new needle and seat may be in order.

This certainly seems to be a common malady with the W-1’s on the 216’s. This is discussed over at the Stovebolt every month or so which tells me it’s not at all unusual.

I pride myself as being a meticulous mechanic and spend way to much time when I rebuild a carb. I even go to the extremes of removing the plugs and making new lead or copper plugs depending on what carburetor I’m rebuilding. When I rebuilt my first carb back in the 50s these plugs were supplied with the rebuilding kits. Me pop was an old school mechanic and had served a regular apprenticeship in the 20’s and he taught me that to do a thorough cleaning ya needed to get at all the passages, so we pulled the plugs on all the carbs we rebuilt. I rebuilt several W-1’s this year and they all suffer from the same problem you describe.

I’ve talked with Jon Hardgrove who owns the Carburetor Shop over in MO and this seems to be a common complaint with him also. His suggestion for starting is the method that I use and it does work every time for me.
If the truck has been sitting for more than 15 or 20 minutes I don’t touch the throttle, that, only pumps more fuel into the engine. I depress the starter with the throttle at idle and it will catch the third or forth time over and then very gently add some throttle. The engine will always clear it self after a few seconds.

I am a firm believer that the percolation problem has always been there with these carbs but the fuels are formulated differently than it was back when they designed these carbs and it’s worse now. I’m experimenting with dropping the float level to cope with the percolation, I’ve already dropped it about 3/32” in a W-1 that I’m running now and it performs just fine and supply plenty of fuel at 60mph with a 4.10 gear but the hot start problem is still there.

Another typical problem I’ve run into with the W-1’s and the Rochester’s is that they both tend to run lean. I have three W-1 684’s and a handful of Rochester B’s that have all been meticulously rebuilt and adjusted right to the spec and they all run just about as perfect as you would expect as long as the choke is pulled out just a tad, around a 1/4” to 3/8”. That gives me a nice smooth even pull all the way up through the gears with no hesitation. Now mind you, this is not an isolated case, this is with three different engines in there different trucks with three different rebuilt carbs. And before you say it, yes, the accelerator pumps are operating just as they should be and the throttle connector rods have no slop and have been adjusted with the proper gauge and the insulator blocks are NOS Bakelite and the heat risers are all opperating properly.

So, one more time, I really think that the fuel today has something to do with the not so perfect rather finicky performance of these older carbs.

Denny Graham
Sandwich, IL

"don't touch the throttle" is impossible as 1938 and up vehicles with the floor mounted starter as they have a feature that automaticly opens the throttle about 1/3 when the pedal is depressed.
I will say I have never had this problem with my W-1 equipped cars. We have had ethanol here for over 15 years + have traveled all over the country using many mixtures of gas.....am I just lucky or what?

Thanks for the advice, folks.

Gene--my manifold heat valve is stuck, probably in the "heat on" position. I guess it's probably time to take the manifold apart and fix it.

Denny--I noticed my engine seems to run a little lean and even when warmed up, on accelerating from low RPM, sometimes the engine power is somewhat "tentative". If I pull the choke out slightly and momentarily, there is a noticeable increase in power. Other than that, the engine seems to run strong and I get about 15 to 17 mpg at 50 mph, which drops to 13-15 at 55 mph. It's possible that the weak acceleration is due to the stuck manifold heat valve--the Chevrolet shop manual indicates that a manifold heat valve stuck in the "heat on" position may result in "lazy" acceleration.

I think my carburetor flooding problem may be due to percolation. Fixing my manifold heat valve and experimenting with an even lower float level might improve the condition.

Mark

Well Gene, I guess as the song says, “You’ve got the, Magic Touch”. Not trying to be a smart [bleeped] Gene, I’m just poking some fun at ya buddy, you know how much I respect your opinions.

But the fact remains that these complaints are just so common that I’ll bet a month doesn’t go by that I don’t here someone asking about them and even the carburetor guys don’t have any concrete answers.

The W-1 and Rochester ”˜B’ carbs are pretty basic carburetors and if you pay special attention to making sure that all the passages are clear and completely open, and that nothing is worn like a connection rod or jet and that the few adjustments and alignment points are attended to, there is no reason that they shouldn’t perform as well today as yesterday. So the only common denominator and the only logical explanation I can think of is fuel. If you or any one else knows of some sort of special trick to keep them from percolating after they are shut down I sure would like to here about it. I would also like to hear a logical explanation of why when you step down hard on the throttle that every one that I’ve seen has a little stumble and goes on it nose for a second, even when the accelerator pump is working properly and newly installed.

And I would also very much like to take a ride in one that is supposed to run smoothly and accelerates with no stumble or hesitation and one that will start first turn over when parked hot.

I’ve seen a lot of guys over the years that will not admit after spending months or years rebuilding their pride and joy, that the performance is anything less than perfect.
Let me say this, that I’m always open for suggestions, believe me, I’ve tried dozens and dozens of them no matter how hair brained they were. And a day doesn’t go by that I don’t learn something new, so teach me something!

And Mark, Gene’s the expert here, so listen to what he has to say. I’m just one of the new guys with my own opinions based on some plain old common sense. But yes, in my opinion you can expect less than optimum performance if the heat riser butterfly is stuck. Once the engine is warmed to operating temperature it should be diverting the gases away from the bottom of the intake. Lets not forget that a whole bunch of GM engineers spent a whole bunch of time designing these engines. To get the best performance out of them I’m a firm believer that every thing should be just as it was when it rolled off the production line.
Denny Graham
Sandwich, IL

Denny,
No problem, no offense.
The point I was trying to make is that it is not a "design problem" with the carburetor but rather some mechanical problem.

At to the "stumble" problem with your engine. You have mentioned that the your engine is worn and tired. You would be surprised how much better it would run with good compression.

I don't know a lot about W1 carbs, but the couple that I have overhauled according to the Chevrolet Shop manual and the instructions that came with the kit, it was not that much of a job, also I never have had a Rochester B carb that needed any choke after a short period of warm up, when the heat rizer flapper valve was working . The Rochester BCs that I have overhauled always used too much choke for our area. There are so many different jets that there should be one that is right for every area. To make the carbs run with close to the right mixture usually a Rochester one barrel suffers from too little of air in the mixture everything else being correct. I also have to disagree with JYD about all Vitron Needle valves being bad from the git-go. I use them for everything from a 5 HP B&S up thru a Chevrolet Q-jet with no problems. Of course in a lifetime of rebuilding carbs as long as JYD has been doing it, he probably has found several Vitron needle valves that leak or stick. I had a carb on a Dixon ZTR mower that had the body of the needle valve (all brass) glued in with new gas varnish, and I had to use needle nose pliers to pull it out.
Different strokes for different folks...

It is true that W-1 carburetors have a tendency to percolate if everything is not right on the carb and engine. A sticking manifold heat valve is a major cause of after fueling or percolation. The addition of the insulator between carb and manifold plus internal changes minimized the problem beginning with the late '32s went a long way toward the problem. By the 1934s it was a minor problem if everything is right.

Modern gas does not help any of the older cars. The blends have a greater percentage of lower boiling compounds which makes several problems worse. Ethanol is only part of the problem. There are hundreds of gasoline blends supplied across the US. Winter blends have much more of the lower boiling compounds so any percolation will be worse if one of those is used.

I suppose that I should just drop this and fade back into the corner, but, I just taint gonna learn anything if I do that, am I? And after all, isn't that the reason most of us join into these forums, to learn or in some cases to teach. If I knew it all, I wouldn't need anyone’s input or opinion on anything.

So I hear the "term having everything right", now just exactly what does that mean? If all the mechanical adjustments are made according to the factory specs, is that "right"?

If everything starting at the fuel tank all the way up to where the cobs come out is clean inside and out, new or fresh, then is the fuel system “right”?

If the proper intake and exhaust manifolds are in place with new gaskets and a NOS phenolic insulator with a new fiber gasket on both sides and the manifold heat valve is working properly and there are no vacuum leaks and the engine has a steady needle at 20in.hg. at idle, is that “right”?

If the ignition system has all new parts installed like points at .018”, condenser, cap, rotor, copper wires, new AC45’s gapped to .035”, a new coil, a new battery, new 2/0 cables, a distributor that has been totally disassembled, checked for shaft and lobe wear, advance spring tension checked, reassembled with the proper lubrication and adjusted according to the factory sepecs, is that “right”?

Now we are left with the basic engine itself, if the cylinder head has been chemically dipped, Magnafluxed and pressure tested, new hard seats, new guides and valves installed and the surfaces machined flat by a long standing competent automotive machine shop, valves adjusted hot to .007” and .014”, is the “right”?

Ok, we’re getting down to the wire here guys, if the engine has 120lbs compression all the way down the line when warm, uses some oil and has a few minor rattles, slaps and knocks because it has 59,537 miles on it, is that reason enough for it, to be “not right”?

And I say again, I’m really open to any solutions, suggestions, as to what you might think is not “right” in this restoration process and am willing to try any of your suggestions.
But remember what I said earlier, I am in close personal contact with three early original 50’s 216 powered trucks and they all seem to suffer from the same minor symptoms.

Denny Graham
Sandwich, IL

Since there are some vehicles that don't appear to suffer from the peculation problem there must be a reason. I am not smart enough to know what it is. I suspect that a major reason for different performance is fuel. The 100+ gasoline blends across the country is highly suspect.

I have rebuilt less than 100 W-1 carbs so still have things to learn. I have been able to get some of the early '32-33s to run very well. Might just be luck but if so then hope it stays with me.

I had the lean condition and the hesitation from the very start after bringing home the truck. The first thing that came to mind was that the carb needed to be rebuilt with special care paid to the accelerator pump and power piston. After spending a week meticulously going over every section of the ”˜B’, which included making a special fixture I made in my Bridgeport that I used for annealing the castings in the oven to flatten the mating surfaces out. This stopped the weeping around the mating surfaces but to my surprise the stumble was still there. I was bound and determined to keep the truck in its stock configuration, which meant keeping the original low shoulder style air horn Rochester B carburetor. I had found several other early ”˜B’s and did similar rebuilds on them over the summer of 2007, but they too, displayed the same performance oddities.

After hearing Jon Hardgrove aka the carbking from The Carburetor Shop talk up the Carter W-1 and express his dislike for the Rochester ”˜B’, I decided to try a W-1 to see if it performed any better than the Rochesters. I had been keeping my eyes open for the 684 models and had by now acquired a couple of decent candidates. After rebuilding the first one and installing it on my ”˜50 to my surprise it acted exactly the same as the Rochester. That is, it seemed to run lean, had a hesitation and by adding a touch of choke it smoothed right out and you could feel the difference in the pulling power up thru the gears.

Now I was starting to look else where for a problem and re-examined the ignition timing and valve clearances. After spending literally weeks going through the entire ignition system to make sure that it wasn't a timing problem and re-setting the valves several times and still making no change in the performance, I was back thinking about the fuel system.

Feeling that I had eliminated the electrical system and timing and the basic fuel system as the culprits I turned my attention to the fuel it self. Having run dragsters in the 50's on methanol and midgets on straight methanol in the 60's and 70's I was well aware of the greater flow rates needed when running alcohol for fuel. I had this gut feeling that the blended fuels had something to do with the lean mixture symptoms because the original carbs were jetted for straight gasoline. I felt that the alcoholic fuel blends might demand that I move up a step or two with the jets. The most nondestructive way to test this out was to find a non-alcoholic fuel blend, which isn’t easy in Illinois. I settled on Aviation fuel since I live on an airport. The avgas has to be blended to have a higher vapor pressure to prevent vapor lock problems at altitude so alcohol blends are not used.
So I ran about 10 gallons of avgas through the engine and that didn’t make a speck of difference.
Now I wish I could say that I’d found the solution, but I can’t. The percolation? I have no idea how you can stop that. I suppose that I can keep dropping the float level till I begin to starve for fuel at 60mph then bump it back up a 1/32”or so and see if that would stop it but I don’t think it would. It’s still not going to stop the fuel that’s left in the bowl from vaporizing from the residual heat. And I’m still hoping to here from some source a logical explanation of what it is that is not “right” in my method of attack.

And by the way, I am getting writers craps but I'm just trying to be as thorough in my narrative as I am at the workbench.
Denny Graham
Sandwich, IL

As an experiment you may want to enlarge the size of the accelerator jet opening.(jet oan a W-1, opeing on a Roch)
The low cover Rochester carbs. had a stumble problem from new on. Some did and some didn't. We replaced many pumps for that reason. The pump circuit was completely redesigned in 1952 so as to insure is was kept full of fuel at all times.
Did you ever experiment with changing (slightly) the length of the link that hooks to the plunger?
Would also be intresting to see what a Carter YF would do.

See now, that’s the first time I’ve heard anyone mention that GM knew about the stumble or hesitation with the early models of the ”˜B’. I was aware that they changed the accelerator well and discharge stop because when I rebuilt mine it was missing the filter screen and spring clip below the pump. I made a new screen and spring clip to correct this. Also the early ”˜B’ had a pump discharge stop that was a split plug where the later ones used the flat ”˜T’ shaped retainer, which are supplied in all the new kits. The later flat top model ”˜B’s that I have rebuilt did have a few settle changes to the pump area, but I’ve never found any documentation on the evolution of the ”˜B’ or reference to why these changes were made. I did notice a mention of the powerglide carburetor displaying a lean condition in the March 1953 Service Release page 3. The correction is to replace the Main Well and Power Valve support with the one used on the conventional models.
I would like to hear where you found your information Gene and I’ll try to look it up. I’ve been adding a copy of the Chevrolet Service Notes whenever I need to fill in an order from the vendors and may have a complete set one-day. Kieth Hardy also has some of them posted on TOCMP that I’ve printed out.

I’ve shied away from re-drilling the jets for two reasons;
The first and primary is that it’s deviating from the factory design or calibration of the carburetor and many of you claim that your engines run just fine when they are “right” and I’m assuming that part of that “right” is having everything up to factory specs.
Number two is that it’s irreversible unless you have access to new jets to put it back the way it was. The carburetor shops do have new jets for the W-1 and Rochesters, but I can damn near buy a new carburetor for what they want for a jet for one of these vintage carburetors.
For instance, on the W-I’s the little 1/4” dia. clip at the top of the throttle control rod costs me eight bucks, the metering rod retainer spring which is nothing more than 2” of .012”(28.5ga.) spring-temper carbon steel wire bent into a loop was another eight bucks, I can buy a 1/4lb spool of that wire for less then that single spring cost me. A standard rod gauge which is nothing more than a 1/8”x 4”x 1/16” piece of sheet metal cost $30 and then there is always the ten bucks for shipping and handling. Of course all these items are probably a bargain if you don’t have access to the dimensions, tools or skills to make them your self. I think you can see why I haven’t strayed to far from the path in my search for a solution.

No Gene, I have not re-bent the accelerator link on the ”˜B’; I have made the adjustments to the throttle control rid on the W-1, which does affect the performance if is not set properly. I’ve only made the factory adjustments to the carburetors and the only adjustment that I have varied from is the float level, which I have dropped slightly in the interest of reducing the percolation.

I do have a YF that I picked up and bought a kit for it but have been concentrating my efforts on the W-1 and ”˜B’. If I could get them to perform the way I think they should then I might mess with the YF.
Gotta go make breakfast for Sweetie Pie, that my big old wife you know!
Denny Graham
Sandwich, IL

First let me say that the early low cover model had problems from day one. I my self would't invest a dollar in fixing one, especially if it were giving problems. We had flooding problems, idle problems, fuel milage problems along with the hesitation problems. I have a 1956 auotmatic choke version on my '50 Power Glide and ot preforms great. May not be correct but it works for me,
The improved version "high cover" came out later in 1951 for the 235 engine. The factory would then OK them for replacement on the earlier cars that were giving owners problems. They always cured the problems and made for happy owners. The 1952 216 came with a high cover carb. and we would then install them on the early 216 cars as well.
The best place to look for the previous years problem is in the next year description of improvements. The improved carbs. are descrbed in the 1952 Features manual, 1952 Service news (late style for 235 also in about Sept 1951 serv news). The place where the best info is found is in the 1949-1953 shop manual. They list all the changes. This may be available in Keith Hardys collection. If not I can send you scans.

Ah ha, now the truth is coming to the surface, I thought for a while I was going kinda nuts. I’m SOOOOO glad to here someone of your caliber speak out on the early Rochester ”˜B’ Gene. I’ve been beating my head against the wall for the last 2 1/2 years trying to make one of those Rochester’s to perform smoothly and that’s why I gave in and tried the Carter. I’m really not all that impressed with the W-1’s performance either.
Now what just how did they take care of the problem of the base size on the later ”˜B’for the 235, they taint gonna fit the smaller bolt pattern of the 216 without slotting the holes.

I did find the 1947-51 Chevrolet Truck Shop Manual and the 1949-53 Passenger Car Shop Manual over at TOCMP and copied the whole fuel section from both. That should keep me busy studying them for the next couple of days.
I also found a copy of the 1951, ”˜52 and ”˜53 Service News, so I definitely have my work cut out for me the rest of the week.
I’ll try to catch up Gene, and once again, thanks for sticking with the subject and for coming up with an answer. One of these days I gotta get up to Milwaukee and buy ya lunch. The got any good swaps or shows up there in the summer??
Denny Graham
Sandwich, IL

Denny, Gene's '50 with powerglide whould have the 235 engine, so the 1956 carb would have the correct bolt pattern. The '52 216 Rochester could be used on earlier 216's. The bolt pattern would be the same.

Yep, I’m aware of that Cleon, I guess I was reading into Genes sentence; “The improved version "high cover" came out later in 1951 for the 235 engine. The factory would then OK them for replacement on the earlier cars that were giving owners problems,” to mean that they were replacing them on all the earlier engines.
However now that I’ve looked at the specs for both carbs I see that the standard 235 carb would have been jetted seven steps richer than the 216 and I’m afraid it would run a little rich on the smaller engine.

I'd be willing to but the farm on the fact that after nearly 60 years most all of these carbs have been rebuilt a number of times and you can bet you bottom dollar that thar was plenty of parts switching going on between any spare carb that looked the same. So to rebuild one with out checking jet size, venturi size and the power piston and spring rate you're just looking for trouble after you install it.

Denny Graham
Sandwich, IL

The high cover carburetor for a 216 would be a #7004600 (unit number). The brass tags were being phased out in 1952 so the tag probably will not be found. The bowl will have casting # 7004516 and the throttle body #7002105. Will have the correct bolt pattern for the 216 engine.
By 1952 this carburetor was sold as a replacement for 1932-1952 engines. It was calibrated to match the 1941-1952 216 engines and probably was to lean for the previous years, especially the 1937-40 that required a richer mixture.
This carburetor could be found on a 1952-53 truck with a 216 engine. That would be a 1/2 through 1 1/2 ton. (some 1 1/2 tons but very few had the optional 235 engine).
Two things can be done to install a 235 carb. on a 216 engine. Either elongate the mounting holes or use a 216 base. The carb. really isn't calibrated for a 216 and would't recommend it.
Years ago I "fixed" a 261 carb. to try on my then new 235 and it had a lot of surging problems.

The best W-1 was the 1949. The next would be the 1941-48. They made little tweeks for 1949. A slight hesitation on these (when every thing else is good) can be one of the check valves for the accelerator pump circuit.Also important that the correct 1949 inlet valve is used in a 1949 as it fits that year only. Also don't know how good todays replacements are. Years ago when a major tune-up was done wich included overhauling the carb. the techs. would just use a new gasket set, two checks and a low speed jet.
The W-1 probably floods over more easily when hot due to the cast iron bowl holding the heat longer. When I am out on the highway and its real hot I give the engine a little cool down period befor shutting it off.
From about 1948 through 1951 we used to install a Carter 414S automatic choke carb. for those who wanted an A.C. The mechanics would install them on their 1950-51 cars to get rid of the Rochester. The had slotted holes for the base so could be used on a 216 or 235. It was a Universal carb. and had an adjustable main jet. It was necessary to make the adjustment on a gas analyzer for the correct air/fuel ratio.
It was a very complicated carb. There was one on my 1950 P.G that I bought from our (woman) office manager in 1952. It ran well but I installed a new and improved Rochester hand choke unit on it. Really ran the same but the Roch seemed to have a little more "pep". Probably due to the 1/16 samller throttle plate on the Carter 414S.
When I mentioned the 414 S to Jon at the carb shop he had nothing good to say about them
I have a new one (had it for years) and tried it on both my 1934 and 1939. Didn't really run any different than the original W-1....(569 on the 34). The 414 developed an idle problem that I never fixed. Don't have any repair info for it. Probably has dirt in the low speed jet but I have no idea where it is.
I have never fooled with a YF but they look very simple. Problem is that they again are a universl carb.
The only problem I have with the present stock carbs on my cars is the fuel evaporation after sitting for a week or two. It has gotten worse year by year as the gas "improves'....and each car has an entirely different carb.
I find that its normal for a W-1 to "run better" with the choke out a hair at low speeds till its really warmed up. Seems to be the nature of the beast.
All my experiance and fooling around is done at 1000 feet above sea level. The cars have all run very differently when in Denver for an example.....and much diferent at 10,000 feet.
My story

Thanks for the historical narrative Gene. It’s really interesting to hear this because it’s really hard to find people with your hands on exposure any more. Us old timers are rapidly disappearing and along with us is the knowledge that we’ve acquired from years of experience.

I’ve been working with the ”˜B’ and the W-1 going on three years now trying to get the best performance out of them and they both leave a bit to be desired. I guess we get used to the way and engines perform in today’s automobiles and sometimes expect similar performance from the old timers, but of course that’s an impossibility.

I’ve never heard of a Carter 414, and you know how difficult it is to find any service information on the Carter Carburetors. Not that I would ever use one of them nor ever find one, but if you ever run across any literature on that model I would very much like to add it to my reference file. My only experience with the W-1 has been with the 684 which was the 1949 version

I would really like to keep every thing as stock as is reasonably possible on my 1950, 3600 which means keeping a Rochester on it. Since the Carter W-1, 684 (hot or cold) doesn’t seem to solve any of the problems I faced with Rochester, I think I’ll swing back to the ”˜B’ and work some more on those carbs.

As to the cast iron base on the W-1, one might think of that in several different ways. Yes it would hold the heat longer than the smaller throttle body on the ”˜B’ but when both are running I often see condensation on the iron bases, so it’s not that they are hot it’s that they absorb the heat after the engine is shut down. One might conceder that the latent heat will conduct to the die cast bowl of the Rochester more easily than through the cast iron leading to the percolation problem.

The funny thing here is that I don’t ever remember having percolation problems with the Rochester back in the 50’s and 60’s and I had several ’50 and ”˜51s all standard shift in and after high school when I was a parts man with Chevy. I drove a stock ’60 six banger 3speed all through my hitch in the service in the early 60’s with a ”˜B’ and had one smooth running six, Fenton headers and all.

So Mark, where did ya go?? Are ya gettin' any thing out of this and have ya gotten that engine to run any better???

Gotta go, I hear my “big old wife” rustling around up stairs, that means Sweetie face will be down in a few minutes and I better have breakfast on the table!
Denny Graham
Sandwich, IL

Denny,

I've been reading this thread every day and learning. When the weather warms up a little, I think I'll look into installing a carburetor bowl drain screw on my W-1, just as an experiment. If I drain the bowl part way after shutting down the engine when hot, and the engine starts with minimal cranking after sitting for 15 minutes, I'l be pretty certain that my flooding problem is due to percolation. If so, the question is what to do about it.

There's a Stromberg A-19122 BXOV-2 carburetor for sale on Ebay. The Stromberg instructions pictured show that the carburetor application is for the Chevrolet 216. Has anyone had any experience running the Stromberg on a Chevrolet?

Mark

I have not but if my memory serves me correctly, the was some discussion over at the Stovebolt a year or so ago. Jon Hardgove at The Carburetor Shop can no doubt give you the some information on that carb.
Denny Graham
Sandwich, IL

Mark,
Would it be easier to install a shut-off valve next to the carburetor. Trun-off the gas supply and run the engine for a minute to lower the level in the bowl.
This would also provide a way to see if the needle valve fails to old back the fuel pump pressure after the engine is turned off, overfilling the bowl.

I've seen two problems discussed here 1)the lean condition when driving and 2)the percolation type symptom after shutdown.

For the percolation, if you have a very reproducable problem at least you can experiment; Try extra spacers initially to get a bigger thermal break. I'd also be tempted to let the car idle and cool down after a hard drive like Gene suggests. Before shutting it down, try experimenting with some bags of ice cubes.

Try packing the carb with ice for a few minutes before shutdown and then keep the ice on the carb after shutdown. Start up as usual and see if anything is different. This should prevent the problem if it's percolation. (Though I would have thought the AVgas would have helped this if it was percolation)

If ice around the carb makes no difference, try just icing (or running cold water) on the fuel line next time, then try the fuel pump, etc. This might help isolate the problem if it's a fuel volatility issue.

The lean condition is trickier as it could be a combination of carb and engine characteristics as well as climate (pressure, humidity, ect).

I had a chev 250 six that had this problem BADLY years ago and extra ignition advance solved it. I increased initial advance and messed with the cetrifigal weights/springs to bring the advance on sooner. Eventually I put in a HEI distributor and it ran even better with no lean condition anywhere. The HEI would have had a different ignition curve but also eliminated the potential variances of the points/condenser such as a varying mechanical dwell or a condenser that behaves differently at different voltages, temperatures or RPM. The fuel today allows for greater advance so this area might be worth experimenting.

I'm curious to see how you make out as I live close to 4000 ft above sea level so am expecting a few issues myself when I start driving this beast.

Some hard starting/flooding on hot restart ideas.

First I have never realy had this problem with my cars so have no first hand experiance. From what I have observed with others with the problem it seems it most often happens on engines that don't seem to have a high starter cranking speed.
Its necessary to have a strong battery, starter, etc. for one thing. A slow starter with lots of cureent draw robs the ignition system causing longer cranking and adding to the problem.

Heat riser stuck sure can't help.

What about pulling out the hand throttle about an inch after turning off engine. This will allow the vapors to escape and any excess gas in the manifold to evaporate. Also will not "pump" the accelerator (1938 and up models) when depressing the starter.

Add 10% kerosene to gas.

Place a small eletric fan under the hood aimed at the front of the carburetor. Would be easier than ice cubes.

Open hood and allow heat to escape when shutting of engine.

Coments?

Well Gene, ya stirred me up earlier this week and I’ve been reading up in the 1952 Service Bulletins. And as you mentioned earlier, by 1952, the Chevrolet Service people and Engineering staff were well aware or the problem with percolation, lean mixture and hesitation with their new carburetor.
There were several changes made to the ”˜B’ to deal with the problem early in ”˜52. There is no sense in me repeating all that is written in the Service Bulletins, they are archived at TOCMP for anyone that is interested. But briefly they redesigned the Rochester ”˜B’ to solve the afore mentioned problems, making changes in the accelerator circuit, idle circuit and reducing the number of holes in the cross bar. The castings were changed so it wasn’t just a rework of the earlier models. So, I would say, if you have a smooth running ”˜B’ on your Chevy, you probably don’t have a late ’49, ’50 or early ’51 models on your ride.
Denny Graham
Sandwich, IL

Denny, Of all the problems I personally do not recall any percolation problems with the early Rochester. I drove my 1941 (with a Rochester) (in 1951) on a 3600 mile trip out west. Went up Pikes Peak, hit south western Colorado and through the Black Hills and never had a hot start problem. This is not to say it didn't happen under some conditions in some parts of the country. In fact I never had that problem until a trip to Omaha in 1982 with my '39. That was when the only gas you could buy in Iowa was Gasahol and it was much worse than Ethanol when it got hot. After driving at highre speeds and slowing down the engine would actually sputter at a stedy 25 MPH.

Boy do I hate it when somebody starts quoting me, and I very rarely will quote someone else, because I do talk a lot and often say things that are taken out of context or just plain misunderstood. So maybe I misunderstood you Gene when you posted this the other day;
“First let me say that the early low cover model had problems from day one. I my self-would’t invest a dollar in fixing one, especially if it were giving problems. We had flooding problems, idle problems, fuel mileage problems along with the hesitation problems.”
This is an exact description of the problems that Mark and I have been describing and exactly the symptoms indicated for the reason they re-engineered the ”˜B’ in late ’51. I’m referring to Chevrolet Service News Jan, 1952 pg3. Not mentioned is the fact that they increased the thickness of the flange on the air horn (high top) but it is noted on pg5 in the description of the Automatic Choke Carburetor. So the problems with the air horn warpage was showing up even in the first year or so after it’s introduction.

Now Gene, if you were to tell some people today, not mentioning any names here, that you replaced a Carter W-1 with a Rochester ”˜B’, they would walk off into the sun set shaking their head in disbelief. I’ve often seen the W-1 on ’50 and later vehicles but rarely the other way round. As you know, some people have absolutely no use for the Rochester ”˜B’ carburetors.
I’m going to see if I can find one of the ’52-’53 Rochester’s meant for a 216 that isn’t to badly “warped” and do some experimenting with it.
The majority of the carbs that I run across have the tags missing so it’s a little hard to tell exactly what you have inside until you open them up. Of course the low top and high top are easy to distinguish so I guess if you find a manual choke high top with a 216 bolt pattern then it pretty much has to be a ’52 or ’53.
I think this sort of discussion could go on endlessly. “Rebuilding a Carburetor” can different things to different people. To some people it simply means new gaskets and pump, to some it might mean dipping the parts into the Gunk for an hour till the outside looks clean and re-assembling the carb. But as I see it, most important on the list is that every internal port and passage is pristine even if that means pulling the lead or copper plugs and that all the threads have been chased clean and all the jets, needles and or nozzles have been checked for wear, size and shape. Then and only then is the unit reassembled and adjusted. So how can you discuss the performance of a carburetor with out knowing from which environment the subject carb came from.
Gotta go, Sweetie Face is clomping around upstairs.
Denny Graham
Sandwich, IL

Denny,
Since you "hate it when somebody starts quoting me," I will try to refrain. Ooops just done it. Well in this case, it was necessary unless I was to paraphrase your statement. Then it would have been my interpretation and not your opinion. Sorry, but that fella on my left shoulder made me do it, I swear!

Your description of the differences in what people consider "Rebuilding a Carburetor" (drat I did it again, sorry but couldn't think of a better way to get the idea across.) were right on! A proper rebuild should include thorough cleaning, checking the individual parts for wear or damage or replacement, reassembly according to "factory" procedures and specifications. But you left out a critical final step. Test the carburetor on an engine similar to the one that the carb will be installed.

I have "rebuilt" a few hundred carburetors over the past 40+ years. While most perform well after going through all the steps you discussed a few do not. It is those (less than 10%) that for some reason do not. I have often discovered parts substitution during the cleaning, checking stage. It takes checking each part with the proper gauge or tool. An experienced eye is a valuable tool.

It is amazing what people have installed in an attempt to get the carbs to run (properly, better, or ????). I recently actually worked on one that had the idle circuit plugged with a stainless rod pounded in the passage, parts from some other carb(s) and modifications of original parts. I wish I would have tried to run it before disassembly to see what it would have done. Despite my doubts, as I was working on it, I managed to get it to run reasonably well. Another old carb was saved and the owner of the car was happy.

I hope you forgive me for the quotes. They seemed necessary to get the proper message across. Besides I think they make my response more interesting. Thank you for the assistance.

Yeah Chip, I think this here subject has a life of it’s own. Your so correct in saying that there is always that one carburetor that everything looks “right” on it, (that’s my favorite word now) but it just won’t seem to tune the way it should. Notice I got away with out quoting you!
I’ve found jets that were numbered correctly, yet when I check them with a pin gauge it’s obvious that they had been drilled out along the way and on a rare occasion I’ve seen a jet that appeared to be eroded a little out of round.
Also some people will try cleaning out a passage or port with a drill bit and thinking that it was clear all they really did was run up a burr at the end of the passage or make the port bigger or oblong. There are a lot of reasons that aren’t always obvious that could make a carb run off kilter. In most cases we don’t know the service history, so ya just never know who or how many worked on over its fifty or sixty year life span.
Although it is briefly mentioned in the service literature you can bet that a lot of the low speed jets are re-installed in the W-1’s with out installing a new jet or reworking the old one to make sure it seals in the taper. This is one of the main reasons for a rough idle or low speed performance in the W-1.
Well, I’m bout burned out on this for now guys, sorry Mark if we ended up stealing your thread, but I think we did lay a lot of ideas out on the table concerning the problems with these carburetors.
Once again, gotta go get supper ready before Sweetie Face, that’s my big old wife you know, gets home.
Denny Graham
Sandwich, IL

Just a little adendum, I just went over to take a look at the Stovebolt Forums and see what I've missed today and Jon Hardgrave is discribing the exact problem and proper way to solve it with the W-1 idle tube. He explains it much better than I can, in fact he is the one who first explained this to me. http://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=504648&gonew=1#UNREAD
Denny Graham
Sandwich, IL

The "idle tube" Jon is refering to is the low speed jet. Denny, I assumed you replace that in your W-1 as it always comes in the kit.
Chipper has also mentioned through the years that it can not be reused...and its in the shop manuals, etc.

Yes Gene, it’s the low speed jet that Jon and I were talking about. Now here I go quoting again, but I guess quoting myself is OK? This is what I said earlier,
“Although it is briefly mentioned in the service literature you can bet that a lot of the low speed jets are re-installed in the W-1’s with out installing a new jet or reworking the old one to make sure it seals in the taper. This is one of the main reasons for a rough idle or low speed performance in the W-1.”
Although the manual says to replace it you don’t have to unless the end is damaged as in torn, nicked or in some way preventing it from sealing in the taper all the way round. What Jon is referring to is that if you are careful you can re-expand the end a couple of times where it was swaged down by the tapered seat. Here is a picture of how I do it: http://rides.webshots.com/photo/2709812840098611668tumimB
I suppose some kits come with a new low speed jet, all the kits that I have gotten from the vendors do not. I assume that Jon’s W-1, 684 kit would have all new jets because the last quote ran around three times as much as the ones I’ve been using from the vendors like JC or Chevy Duty.
And I might add that I just finished three W-1’s using reformed low speed jets and the low speed performance is just, as it should be. Denny Graham
Sandwich, IL

Denny: So dudes might not get confused, you might want to explain that part being shown in the photo on the link given above is the air horn nozzle and not the low speed idle tube. The tip of the low speed idle tube is what needs to be expanded.

Your absolutely correct JYD, it is technically the main nozzle, sorry if I confused anyone. I’ve also seen it referred to as the idle-tube which I suppose is also an incorrect reference. I’m not a very good technical writer and have a problem with semantics and getting my point across at times. Adding to my inadequacy is that I’m posting to too many different forums on too many different subjects so I’m often times confused as to just who I’m talking to about what. So, as I said before, I’m bout done here, one last word and I’ll leave the rest up to the experts, remember now, I’m just a back yard mechanic.
There is probably something wrong with this also but my interpretation is that during low-speed operation the main-nozzle is feed by the low-speed jet which is located at the bottom of the passage and at this stage it is the delivery point for the low-speed circuit. As the throttle is opened and the metering rod is withdrawn from the metering jet the main-nozzle then becomes the discharge point for the high-speed circuit also.
I guess the point I was trying to make is that if the main nozzle is not seated properly, you will mostly experience noticeably poor low speed operation.
So if you see anything wrong with this please feel free to make the corrections.
DG

Yes, the main nozzle must be seated correctly and, for seating purposes, the nozzle shown in the photo does use a small copper washer that is installed on the base flange of the nozzle. This small copper washer usually comes in the repair kits and it should replace the original washer when the carburetor is rebuilt. However, the photo showing a tapered tool being inserted into the opening of the main nozzle is confusing, so you might want to change your photo to show the tapered tool being inserted into the actual low speed idle tube instead of the nozzle. That will make it much easier for the novice to understand the explanation as to why this is done when the photo is viewed.

Never giving up does not mean continuing to do things the same way; it means to keep on working toward your goal no matter what, and learning from your mistakes. Lots of mistakes in my replies, this what happens when ya got to much on your plate, confusion! What I’m trying to remember from last year is really foggy and I should have just kept my trap shut in the first place and not spoiled Marks thread. And rather than miss lead any other new guy that is reading this, were it possible to go back an retract what I was posting in my manic state I would. Boy, did you ever just want to leave the room in a conversation, well I do.
You are 100% correct, the picture was wrong. It was a compilation of pictures that I took in a photo session documenting the work that I was doing on one of the carburetors. I had a bunch of parts lied out on the bench and just grabbed the main nozzle for the pictures. I’ve corrected the picture and the previous link is dead. This is the picture that I meant to post; http://rides.webshots.com/photo/2843473480098611668BrdNfp with out the top frame.
DG

Denny, Don't beat up on your self. You shared a whole lot of good stuff with us on this thread. The positive info offered out weighs the mistakes a zillion to one. One thing about this site is that those that point out some minor differences add to the learning curve for all of us.
One of the major values of this site is the amount of sharing of all of the knowledge that our club members posess. If this site was not here, just think of how much of this knowledge and talent would just be locked away and never shared.

Good job!

Well tks Mack, I'm just trying to do to much stuff right now and when I have to dip back to what I was into 6 or 8 months ago I the memory blurs.
Just tryin' to finish up a couple of '51 Philco radio/phonos this week and I got about a dozen RCA 45 players on the shelf before I can get back to the truck this spring.
I'm also at the same time experimenting with casting urethane for knobs, vulcanizing rubber for isolation grommets and mold making in the machine shop for all of that. So I'm bout at my limet.
Denny G

Denny,
Most of the casting urethane compounds do not have UV resistance and will deteriorate relatively quickly in sunlight (not days but months). A UV resistant coating (can be sprayed and function like a mold release) will give longevity. Urethanes range from rock hard to ultra-soft so they work well in many applications. I spent many years in the polyurethane business so may be able to help if you run into problems.

We’re getting waaaay off subject here, but thks Chip.Been looking at products from several different sources, Freeman Mfg & Supply (Hobby Cast), Smooth On and rightr now I’m waiting for an order from Alumilite. Need to learn some about color and creating swirl patterns.
The rubber parts could be used for automotive parts also, I’m using uncured rubber I picked up from a local Bandag tire re-capper and I’m curing it in “my big old wife’s ” oven, when she’s gone that is.
Thanks for the offer, I’ll keep ya in mind.
Gonna have to start talking truck again in a month or so I need to get some of these new skills developed and finish up the winter projects.
Denny Graham
Sandwich, IL