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Hello

I have just rebuilt the fuel pump and had the carb rebuilt by a reputable local mechanic that has several classic cars of his own (I won't tell you though they are chevy's). The problem I am having is too much fuel is coming into the carb and leaking out all over. He said the float wasn't "Heavy" and seemed OK. The needle valve was replaced and new gaskets.

My question is could there be something wrong with my rebuild of the pump that is making it pump too much fuel and over riding the float and needle valve?

I appreciate any and all help.

Thanks,

John H. in Ballston Lake, N.Y.

Place a pressure gauge on the fuel pump to see how much pressure it is has.

I would say the there is still a problem with the float or needle valve. You can hook a pressure gauge to the outlet side of the pump is you cant to check the fuel pressure. I would think it should be between 3-5 lbs..

Pump output pressure normally depends on the diaphragm spring in pump unless the diaphragm is under too much tension. If the spring is the same one, then that doesn't leave much in the pump. Any chance when you rebuilt the pump the diaphragm was not flexed to the full travel limits when you screwed the halves together and is under tension. Usually there is very little flow and possibly even a damaged diaphragm along with more pressure when that happens.

What carb, pump and car are we dealing with here???

Doesn't much matter if we are dealing with a six, 120, custom, v-12 etc, they all have similar functioning fuel pumps and carburetors. Pressure is pressure, but I don't know how you can get too much presure out of a FP, as it is produced by the strength of the diaphragm spring. If a diaph is not flexed enough when assembled I think it wqould perhaps rupture but for sure not produce too much pressure.

He is describing a flooding problem so perhaps float level is set incorrectly, float has a hole in it and is sinking, or it is binding in its movement OR there is foreign matter in the needle and seat. Often when this problem occurs with one of our rebuilts and a customer returns it we find teflon tape in the needle/seat. Teflon tape should not be used on the fuel system, it is useful on pipe threads only, such as the heater tap in the head. The fuel system pressure is retained by the flares in the fitting and the mating surface on the pipe, not by the threads on the pipe fitting.

+1 on what Fred said.

I had an issue with the float on my carb. It became porous and allowed fuel to leak into the float. The heavier float now allowed fuel to flood the engine.

My quick fix was to heat the float with a hair dryer and I saw a small porous area on the float. The hot air also helped to force out and dry the float. After it cooled down I used a soldering IRON (not a torch) to "tin" over the porous area of the float.

Seven years later is is still running great.

"it is useful on pipe threads only"

I believe on the WGD (and most likely others) the fitting on the carb itself is pipe thread, with a brass fitting going from pipe to flare.

On my fuel pump, both sides had a brass fitting from pipe to flare. Pipe thread usually needs some sealant to seal, but i wouldn't normally think it'd be an issue with the low pressure's we're dealing with here.

I didn't use teflon and they didn't leak, but I've seen teflon used without issues also. As Fred mentioned, carb rebuilders run into it often. Cliff Ruggles and other known careb specialists won't warranty a carb with teflon issues after being installed.

A tubing connection fastened to a fitting with a flared end and pipe thread on the other end can leak at either the flared or pipe connection end, or both. I know, I have had to fix leaks on the flared end, on the pipe end, and some on both ends.

(o{I}o)

Yes JW. I've ran into the same thing many times. Ususaly the flare will get just slightly distorted and allow for minor seepage that some tape or sealer will easily fix. Replaceing lines or special fittings can be sometimes be difficult. I don't like the tape or sealers but they will fix the problem usualy fast, cheap and very effective.