Coming from Carter's own service information, and confirmed by my own experience...
On Carter W1's, the idle circuit continues to be the primary source of fuel well beyond "idle speed". Especially under "no load" conditions. So... with a plugged idle circuit the engine will run rough well up in revs. Even on the road under load, the idle circuit doesn't completely drop out until somewhere above 15-20 mph.
As per Jon's post above, delving deeper into the idle passages fixed MY problem.
I have to correct my earlier “no” with a yes. I just spent some time reading how the Idle or Low Speed Circuit operates and that does seem to be the exact range I am having trouble with. This page is very informative giving me a better understanding of what I am looking at and what it is suppose to do. https://www.carburetor-blog.com/knowledge-base/w-1-low-speed/ Everyone’s comments are starting to make sense now. -now that it is confirmed that the Idle/Low speed circuit is the issue. -what do I try first Thank you
A cheap, easy, and fast way to blow out the low speed jet and passages.
Remover air cleaner. Place #3 spark plug wire on # 4 spark plug and #4 wire on #3.
Start engine and tromp down gas pedal rapidly several times. The engine will back fire through the carburetor and blow out the dirt of the low speed jet and idle system.
If this does not work there is probably an assembly fault in the carburetor.
If that doesn't fix the problem, try removing the idle mixture screw and direct a very high pressure blast of air into the hole the screw came out of.
If that doesn't work, you will need to find someone who can remove the slotted plug, idle jet, and the copper plugs in the ends of the drilled passages. As Jon said, at the very least the plug at the end of the upper cross-passage will need to be removed. The passage(s) and economizer orifice will need to be cleaned using the PROPER gauge sized extended reach drill bits. It is VERY important to know the proper size to use for the economizer orifice in your specific carburetor model, and not ream it oversize.
I had to go all the way with my carburetor. I soaked and flushed with every kind of solvent I could think of, and directed air in both directions through the system. Liquid and air flowed through the system, but reassembly and re installation gave the same poor results.
Only a small amount of reddish stuff came out of mine when running the drill bits through, but the effect of cleaning was dramatic.
Good luck.
PS The link you provided for the explanation of how the idle system works is excellent, and gives almost exactly the same explanation the Carter literature gives.
I should have been more clear. Sorry about that. When I said idle screw, I was referring to the "idle mixture" screw.
Most old carburetor cores will still have the vacuum fitting in them. (the ones I have do) Possibly you could contact one of the members nearer to you than I who rebuild Carter carburetors and ask if they will sell you one?
Otherwise, it's been a while since I had mine off, but isn't this the fitting you are looking for:
I own a 1936 Chevy Master coup that I inherited from my pop's earlier this year after sitting for 3 years. I was able to to get it to run after freshening it up and it ran ok with some idle issues but the biggest problem was at high speed 45-50 the engine would die out. Long story short I had the W1 rebuilt by Rod's carb in Glendale AZ where I live and all my issues resolved. I agree with the guy's above that there is some thing clogged and it need's a rebuild.
I’m going to try the swapping #3 & 4 spark plug wires to blow out system. The carb is newly rebuilt so I can only assume it ingested sediment from the tank
Please read back through this thread as well as my post from about a month ago. I would not necessarily assume it is dirt from the tank. In our case we are getting small rust particles from the float bowl itself.
I would also be cautious that assuming that because the carb was just “rebuilt” that everything was clean. If I remember correctly this carburetor has never idled properly on your engine. As noted by others who posted to your thread if the rebuilder did not remove all of the threaded and pressed-in plugs the passages might not have been properly cleaned.
The idle passage is very prone to blockage because it is so long and small in diameter.
I’m actually starting to wonder if my timing is off with all of the messing around with stuff I’ve done. What sow the screw with the spring suppose to do, it seems to do nothing audibly noticeable?
The screw absolutely nothing and now there is black smoke coming from the exhaust which started since trying the 3&4 swap and Erving engine. Once the wires are correct she is now backfiring occasionally.
It probably would be good to start from the beginning of a tune-up and that is a compression test. Fuel and electrical items will not compensate for mechanical issues . Once you verify compression is good then you can diagnose further.
Thanks all for the advice, turned out to be a defective rebuild. She runs great now but.. -ready to go for a spin and the brake pedal went to the floor. I checked the master cylinder and it was empty. After filing and pumping a few times I have a full pedal. Should I be concerned? - Took her for a spin and decided to get gas not knowing how much is in her. Have been putting gas in her two gallons at a time until today. I might have put 3 gallons and gas started pouring from around the tank somewhere. Is it normal for gas to put out if the tank is full? Thanks as usual Michael 38 Master Sport(sport maybe?)
There are 2 standard openings in those tanks, the filler neck which may be a 2 piece with a rubber hose joiner and where the guage sender fits into the tank. Either 1 is a possibility or there is a rust hole somewhere. Tony
But the seller told me the tank is new, like I believe that. The gauge never worked properly, stuck at half a tank too. A hole was cut in the trunk floor so something was done in the tank area. Another mystery to unravel. Keep you posted.
