Fuel drains from carb

[BigIrish]

The carb on my fairlane has the fuel inlet on the bottom of the carb fuel bowl. After a week of sitting the carb is dry and have to crank it awhile to get fuel back in the carb.

Is this a bad or going bad check valve in the fuel pump? Should I replace the pump or install an inline check valve?

Side note: check out this crimped fuel line. Whoever ran the line conveniently put it in a place where it gets smashed by the suspension. I don't know how the thing even ran in the first place!

 

[King Herald]

The mechanical fuel pump consists of two check valves. I'd check them out first. No need to add another.

 

[HOT40ROD]

What carb is on the engine. Some holleys will drain back if the power valve is bad. It actually will drain the fuel into the engine.

 

[T DRIVER]

My Guess

show any leakage on floor,intake,frame look real close. Had the same problem but found that there was a small hole in the bowl fixed it with J B weld took care of that so far. [S

 

[ShovelHeadShawn]

i had the same problem on a sbc. it turned out to be a bad diaphragm in the fuel pump. replaced the pump and never had the problem again.

 

[BigIrish]

Well a fuel pump was $22 so I went ahead and replaced it. There are no external leaks and inside the intake manifold is dry, so I don't think it's leaking into the engine. Not sure what kind of carb, can't find any markings on it anywhere. It's an old 2bbl, castings look pretty rough, maybe a repop or generic version of something?

I'll let it sit for a week and let you know. [P

 

[HOT40ROD]

Does the carb look something like this. If some before you crank the engine take the top of the carb and look to see how much fuel is in the bowl.

Remove the center stud and the six screws that hold the top on the carb. left it up and turn off to the side. that way you will not have to disconnect the choke.

If the bowl is empty the power valve could be bad or the jets are loose. If the bowl is full then the issue is not in the carb. Then check all of the rubber hose connection not forgetting the one at the tank and also check for any holes along the fuel line. look in area were there is dirt around the line and all connecter that hold the line to the frame. You said you change the pump so there could be a slit chance that it could be the pump.

 

[BigIrish]

Hey, that's it! What kind of carb is it? Mine's missing the data plate (and auto choke and dashpot...)

OK, will check those things. When I got the car all the screws around the accelerator pump were loose & leaking, so wouldn't be surprised if the jets are loose too.

 

[HOT40ROD]

A leaking accelerate can cause that issue also.

The carb is a autolite 2100 series. If you look on the the right side (DS) of the carb in the bowl area you will see what looks like a circle with some numbers in it. The numbers will be one of the following. .98, 1.01, 1.02, 1.14 or 1.23. these number are the CFM numbers.

.98 is 190 cfm
1.01 245 cfm
1.02 240 cfm
1.23 300 cfm

 

[cking894]

Your issue may not be a mechanical problem. The new fuel mixtures are much more volatile then the fuel we got years ago. The gas evaporates at a much faster speed which cause the fuel bowl to be empty.

Keith

 

[BigIrish]

A leaking accelerate can cause that issue also.

The carb is a autolite 2100 series.....

Ahhh, thanks. I rebuilt one a few years ago, what a piece of cake! If it continues, I'll just rebuild it.

Thanks!

 

[brokenhead]

the carb in my old truck goes dry about that often, but it just evaporates. Not so much now as is it is pretty cold now.

 

[BigIrish]

New fuel pump seems to have solved this issue. Thanks for the input everyone.