VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 1928 Carb Trouble

My 28 carb seemed to function OK when I finally got it to run but when I removed the broken inlet screw I could see a lot of dirt inside. Because the out side was so dirty, I decided to send the carburetor to a Professional for rebuild.
The old saying is "If it's not broken don't fix it" applies to this case.
After rebuild the car would run OK for awhile then when you parked it the fuel would run out the vent.
Sounds like a float or needle valve problem. Checked the float and looked for dirt in the bowl. Two weeks go by and no problems. Suddenly driving through the neighborhood the car starts to run poorly. Black smoke out the tail pipe, misfires, and no power. Took carb off and back to the Professional. I watched him check everything and we could see no problems. Even checked the needle valve under magnification, vacuum, and pressure.
Back on the car it ran for twenty minutes, black smoke, flooding again.
By the way I'm running the vacuum fuel pump with a Hastings inline fuel filter that's been changed twice. I ordered a carb kit and decided to try it myself. The float level was set at about 1 1 /8 inches which should make it lean. My service manual says 1/2 inch which should be rich. I put in the needle set the level at 3/4 inch. When set at a 1/2 inch the needle would bind when the float was fully down. Back on the car it ran for about twenty minutes on the road, Black smoke, no power, but it didn't flood out the vent when I finally limped it back into the shop.
What am I missing? This is by far the most simple car I've ever worked on, but it has my number on every basic task I take on.
As always I appreciate your help. I hope I'm not becoming a pest. :confused:

Mike B

1928 2dr sedan
1956 2dr sedan

It may not be the carburetor. If it runs ok then rich and does not overflow the bowl, it is most likely the fuel pump. The problem is overfilling the pump and then feeding gas directly through the vacuum line to the intake manifold. The test is to take the vacuum line off the fuel pump and if the engine smoothes out and runs like it should it is the tank. Just had the problem with my '19 FB and others have had it too. Not too common but enough that we have a lot of experienced 4 banger tourers that know the problem and solution.

There are several possible problems. None are too tough to fix. Do you have the original '28 pump with stamped metal top and 4 screws or the die-cast top with 8 screws? If the float in the pump has a hole in it (likely if it has not been looked at in a while) then it will overfill. If the brass seat on the vacuum line (die-cast top) is loose, tilted or dropped out (super glue it back in making sure that it seats all the way into the top).

If that does not fix it then let us know what you found. Second thought, let us know either way.

I once had a finicky 28 carburetor. It turned out to be a defective needle and seat. It looked perfect but would stick and/or leak. Watch out for the ones having a neoprene tip. I don't think they get along with today's gasolines.

-Ron

Chipper. The fuel pump I believe is the four screw and was rebuilt a few weeks before the carburetor. I'll try a clear vacuum hose this evening to see if fuel is coming in that way.
Thanks
Rustyfender. I changed the needle valve last night. Both the one I took out and the one I put in had the black tip. The brass seat was the same size but different.
Thanks

Mike Chip is right the vac tank is likely to be to source of you problems disconnect the vac tube from the manifold and see if the black smoke problem persists , then look at the float or the two hooks on the vac tank lid they must be correctly timed to allow the valve to close.I have had this problem several times over the years mostly the float cracks and will not close the vacume of so the fuel gets forced fed into the manifold ,I always have a spare float under the seat.

Mike,
Just unhook the vacuum line and hold your finger over the end of the tube attached to the manifold. If you don't hold your finger over the tube then the mixture will be lean and you will get a rough idle.

I rebuild the '28 carbs so am very familiar with them. The rubber [actually most are Viton(R)] tipped needles are ok. They stick quicker due to weight not the rubber tip. There will be an article on carb needles sticking in an upcoming G&D. Should be in late summer issue as it is just ready to send in.

I checked his vacuum tank for him and as expected the float had sprung a leak and sunk. Provided another vacuum tank and waiting for results.