gas cap

[copperjohn]

I have a '36 Buick with a rounded gas cap without any visable venting. I've been having trouble with the car dying out after driving for a short distance, 2-3 miles. I have an older electric fuel pump that sometimes helps and sometimes not. After sitting for 5 to 10 minutes it will start and run fine but die out again down the road. I'm thinking of replacing the cars fuel pump but I'm wondering if the gas cap has anything to do with this.

Any help will be greatly appreciated.

[unimogjohn]

John, the cap should be vented. To check, wait until the engine stalls, run to the gas cap and take off slowly. If you hear a wheeze/hiss when you open it, then that tells you that it has pressure inside, this is a no, no.

I would recommend that you put in a temporary see thru plastic filter just before the carb so you can see what is happening to the fuel flow when it stalls out. If you still have fuel in the filter then you probably have a carb issue. If no fuel, you have a pump or glogged fuel line or tank problem.

These filters are only a few dollars at any auto parts store. Just make sure you get the one that fits your fuel line.

[Guest billbudd]

Hello, Just wondering what Model 36 you might have?

Bill Budd :confused:

[50jetback]

From the 1936 Shop Manual

Never use a past model gasoline tank filler cap that has no vent because the tank will collapse when same is used.

An unvented cap will certainly cause the symptoms you describe.

[copperjohn]

Billbudd, the car is a Century. I want to thank you all for replying. I'll try with a vented cap but what is puzzling is that I had no problem last summer. I've ordered a rebuilt fuel pump and will also replace the electric pump. They are both old and the electric pump is noisey.

[Mark Shaw]

I suggest a rotary fuel pump over the noisy diaphragm type...