Fuel drawing back?

Carbs, Pumps - It's all a Gas!

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Root Beer Stand
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Joined: Sat Jul 12th, 2008 4:28
Plymouth: Special_Deluxe_4dr_Sedan
Location: West Central Ohio

Fuel drawing back?

Post by Root Beer Stand » Tue Jul 14th, 2009 3:08

Noticed this summer the fuel is leaving the carb if I leave "Lucille" set for more than a couple days....not leaking so I am sure it is going back into the tank. Faster when parked on an uphill incline I have found

A little priming gets her going but still a PITA.

The manual says there is a check valve in the carb and one in the fuel pump. Both are working great save the fuel drawing back to the tank so I really don't want to tear into either just yet.

The easiest place to add a new 3rd check valve would be in the fuel line going into the carb which would cause the fuel to draw against a closed valve when the fuel pump check doesn't hold and the carb bowl should remain full. (I think)

Think this will work?
Any suggestions other than a carb and pump rebuild right now?

RBS
"Lucille" the Grandkids, the Mrs, and me!!

roughn3ck
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Plymouth: Deluxe_2dr_Sedan

Re: Fuel drawing back?

Post by roughn3ck » Wed Jul 15th, 2009 2:50

your not running ethanal in it are you becouse your car wont run very well on it and it will vapor lock and ethanal boils at 90 something degrees and that might be the reason your carb is dry after being ran and then shut off

Root Beer Stand
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Posts: 252
Joined: Sat Jul 12th, 2008 4:28
Plymouth: Special_Deluxe_4dr_Sedan
Location: West Central Ohio

Re: Fuel drawing back?

Post by Root Beer Stand » Wed Jul 15th, 2009 6:22

Takes a couple days to lose fuel, sure there is some ethanol in the fuel.
All gas in stations has some but not enough to be evaporating that soon.
Sure of that.

RBS
"Lucille" the Grandkids, the Mrs, and me!!

Johnny_S
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Location: Northern Colorado

Re: Fuel drawing back?

Post by Johnny_S » Thu Jul 16th, 2009 11:33

This is a fairly common issue with these old carbs. If you start them every day ... not much of a problem. If you let
them set for more than a couple days .... can have some starting issues. A rebuild will usually help some .... gasohol can be part of the problem both with original gaskets and with evaporation.

I can usually just hit the accelerator one time and set the choke then crank until it starts. Or, if that doesn't work I just pump it a half dozen to a dozen time and generally that works. Occasionally I will flood it and have to let it set for a short while. Another alternative is to put a 6 volt electric fuel pump in line with the mechanical one (near the gas tank is best) and just switch it on to prime the carb. That solves pretty much all starting problems related to fuel delivery IF you don't deliver more than about 2 or 3 lbs of fuel pressure at the carb. You can then shut the electric pump off after start up and just run on the mechanical one.

John

Root Beer Stand
Deluxe Member
Posts: 252
Joined: Sat Jul 12th, 2008 4:28
Plymouth: Special_Deluxe_4dr_Sedan
Location: West Central Ohio

Re: Fuel drawing back?

Post by Root Beer Stand » Fri Jul 17th, 2009 11:34

Sounds like a good plan however still wondering if a check valve would help.
Noticed if the car is parked on an uphill grade the problem comes in half the time or less, level takes 2-3 days.

RBS
"Lucille" the Grandkids, the Mrs, and me!!

Johnny_S
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Posts: 879
Joined: Mon Nov 4th, 2002 3:59
Plymouth: No_Plymouth
Location: Northern Colorado

Re: Fuel drawing back?

Post by Johnny_S » Fri Jul 17th, 2009 3:53

If the problem is in fact a return of the fuel to the tank or back into the line .... probably. I'm not so certain that's the issue however. It would be worth a try however!

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