Fuel Pump

[joereich]

Hello GS guru's
I have a problem with my car, I sent the carburetor last fall to be rebuilt by All American Carburetors in Fl, and the did a great job, but this year I am having a new problem, if I let the car sit for two weeks or more the carburetor looses prime if I poor a small amount of gas in the carburetor it starts up with out a problem. Any suggestions do you think my fuel pump is going?

Thanks

Joe

[WkillGS]

That's normal.
Fuel simply evaporates from the carb fuel bowls.
You can add an electric fuel pump inline and use the 'passing gear' signal from the gas pedal linkage to trigger a relay and turn the electric pump on......turn ignition on, floor the pedal for a few seconds to fill the carb, then start.  Elec pump will also turn on when under full acceleration.

I bought an Airtex E8016S from Amazon ($28) for this purpose but haven't installed it yet.

[GreatScat1965]

an auxiliary electric fuel pump is a good idea on any carbureted vehicle, actually a very good idea. That said I'd try still want to find out what is the actual problem. Fuel should always present in the bowl of the carb. You should be able to disconnect the fuel line at the carb (say doing a old school fuel pressure test) and the car should start and run for a minute or two on the fuel in the carb. If it won't the next question would be why is the bowl empty.

Check, after 2 weeks of sitting, take off the air filter and work the throttle (WOT) several times. If you do not get a full squirt from the accelerator pump each time than the fuel bowl is almost empty. Some fuel may have evaporated from the summer heat, but most likely the rest dripped into the intake manifold. If it squirts good, note if the choke is fully closed at that point; it should be. If not just adjust it more "rich" and try to start it.
You mentioned having the carb rebuilt, Did it do that before the rebuild? It is very possible the carb may need looking into again if the bowl is going dry.

If you want to check the mechanical pump there are two tests, pressure on the outlet side and vacuum on the inlet side that need to be to spec. any old shop manual should have the procedure and some parameters to compare.

I hope this helps.

Jerry

[joereich]

Thanks for all that info, I called the company the rebuilt the carb, they said it's the ethanol evaporating, I know the new gas is not very good but I never had the problem before.

Thanks

Joe

[GreatScat1965]

So they are telling you that metnonal gas only evaporates out of a rebuilt carb?  Hmmm.

[vinnie]

Having somewhat of the same problem with a hard starting car. I'm thinking part of my problem is the heat trapped under the big 2x4 air cleaner is causing the fuel to boil when i shut off the car. This will be up for discussion for those of you attending the Nprthwest Ohio gathering on September 10th. Until then, any suggestions will be looked at. All ready has the electric pump installed inline.

Glenn

[GreatScat1965]

Having somewhat of the same problem with a hard starting car. I'm thinking part of my problem is the heat trapped under the big 2x4 air cleaner is causing the fuel to boil when i shut off the car. This will be up for discussion for those of you attending the Nprthwest Ohio gathering on September 10th. Until then, any suggestions will be looked at. All ready has the electric pump installed inline.

Glenn

Vinnie, Boiling the fuel out of the bowl is always a possibility. If you are using an electric choke, block off the exhaust crossover in the intake manifold. That will a lot of heat out of the carbs. Another suggestion would be to use a lower temp t-stat if you are not already.

The easiest thing would be to just open the hood when you park the car for the evening. It sounds too simple, but when a engine is shut off, the temp goes up temporarily.  I got into that habit years ago from a BBB racer friend. This one is easy and free.  See you in Defiance.

Jerry