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gas problems 1929 chevy


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rotlve
New User

Aug 15, 2009, 7:49 AM

Post #1 of 4 (2397 views)
gas problems 1929 chevy Sign In

I restored a 1929 chevy. I have to put gas in the manifold to get it running. It runs till I shut it off, but 10 minutes later it will not start . I pulled off the carb and noticed no gas in the bowl. I figure the gas is running back to the tank. Is there anything I can do besides putting a electric fuel pump on?

Thanks
Steve


Tom Greenleaf
Ultimate Carjunky / Moderator
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Aug 15, 2009, 8:44 AM

Post #2 of 4 (2390 views)
Re: gas problems 1929 chevy Sign In

You gotta help me a tad with that age. Is this an "updraft" carb, gravity fed fueled or pumped fuel?

If gravity feed there should be a drain on bottom of bowl to let water out and most would use a sight glass to show water instead of a filter you would see it and clean it yourself. If you installed a filter in line it should only be a fine screen not too limiting as fuel might have trouble going thru current style filters.

There was still a needle valve back when of lesser material than will be thrilled with the fuel today. Sometimes they would stick even back when and a tap (carefully please!!) on carb (use plastic and all care not to hurt anything) would set it free.

I'm guessing this isn't your daily driverCool so make a habit of only having the fuel you need for a drive and run it dry when finished. If it will sit for extended time use "Stabil" for the fuel or it may have a drain to use it up elsewhere and use fresh more often.

If this does use a pump the thing may have lost it by now. Rebuild kits should be available. In older pumps they were screwed together with a diaphragm that could be replaced and the action was to allow fuel to travel just one direction in a "reed" type idea of rubber like flaps didn't allow them to pull gas from source and just push it back.

Hope that helps some. I still have some old stuff but not quite that old - principles apply same as always,

T



Guest
Anonymous Poster

Aug 15, 2009, 9:26 AM

Post #3 of 4 (2381 views)
Re: gas problems 1929 chevy Sign In

Tom
My chevy has a fuel pump and I rebuilt the pump and had the carb rebuilt at same time.

S


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 15, 2009, 10:47 AM

Post #4 of 4 (2372 views)
Re: gas problems 1929 chevy Sign In

OK: Something didn't go as planned and yes your description of fuel sucked backwards is an issue.


Thoughts: Carb and or pump parts too old for newer fuels. Rubber hates alcohol in much of our fuel today as does gasketing. There should be a check valve at pump to disallow flow backwards. Direct vented carbs would be dry after a long stretch but not 10 minutes.

You could probably find an in line check valve from a newer GM fuel filter and create line to make it fit. Carb job may not be working properly - anyone's guess for now anyway. Specs would be near impossible to come by but floats used to be weighed. A downdraft carb should operate at idle with top removed and one toothpick holding just the right stuff down to watch it work and the true level of fuel in the bowl.

Again - my know how is the basic principles of operation. Carbs are glorified toilet tanks with meter flush action and refill. The fuel pump is rubber flappers (or should be) that with pressure of spring on diaphragm only allows fuel to pass to carb when needle valve is not shut tight and the pressure within locks a rubber disc such that fuel doesn't return to tank. One hair of debris in needle valve or either of the check valves stops the proper show. When running things are too fast for small issues. (ever have a "T" handle air pump that would work fast but if too slow with it - it would leak down?

If parts are an issue if there's still a real auto parts place near you (Napa) is one that has stuff hidden out back uninventoried around me and some old timers if still there can either find stuff or know where to find stuff - not computerized in some cases.

Slight guess: Neoprene ( a Dupont '?' creation) is rubber that is tolerant of fossil fuel. Rubber is not so literally paper products, asbestos, and leather was used - pretty smart stuff for old engineering!

If in the course of re-doing carb and fuel pump the white Teflon tape (another trademarked item) was used it can and will NOT dissolve and mess up the show if shards of it passes the wrong spots. Must be removed with tweezers and never to be used on threaded fuel items!

You are actually lucky in some ways as Chevy used threaded things still known and available. Ford (Henry I) was a clever a$$hole who decided to make non metric or SAE threaded stuff such that you were screwed without his unique threaded parts all over early vehicles. Most drilled them out for standardized threads of anythings.

A problem now is most who know these cars are not with us or no longer care. Oldest engine I own and have is a GM, John Deere, Waterloo, and Kohler joint effort that I've owned for some 40 years - now a 62 year old engine.

Hope others are watching. We have some old pharts here.

Know that some parts can be made with sheet stock for gaskets. You need to be good with an Exacto knife and leather hole punch - smile!

Keep at it,

T







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