Have you verified that your choke plate is closed when you're having this problem?

 

If I had to guess I would say it looks like a Holley one barrel (possibly a model 1945). It is definitely a high inlet. Are you seeing any wet spots from leaking fuel anywhere? Have you checked for possible engine oil dilution?

"Do you have any idea how long the engine should crank to get gas to the carb if the bowl was empty ? I'm thinking it shouldn't be more than a few seconds, but I don't know."


Depends a lot on the fuel pump condition but 30 seconds sounds possible. You need to do the pressure test.

 

-"Have you verified that your choke plate is closed when you're having this problem?"

Yes, the choke is closed.

-"Are you seeing any wet spots from leaking fuel anywhere?"

No fuel leaks visible.

-"Have you checked for possible engine oil dilution?"

Do you mean gas in the drain oil? How do I know?

-"You need to do the pressure test."

I pulled out the fuel filter to see what I needed to fit a pressure gauge. The fuel filter was clean, but I noticed three ports (see picture).

http://pic.atpic.com/2354021/600

1) If I blow in the outlet, I can feel air comes out that side port. Is this right?
2) If I pour fuel into the line leading from the fuel pump, the fuel leaks back into it. Doesn't this mean the fuel is not being kept in place by a check valve in the fuel pump?
3) Is the fuel pump suppose to check the fuel drain back?

 

The side tube on the filter is a ported return to the tank and yes air should come out it if you blow in the outlet. This ported return is why when you do a pressure test the fuel pressure returns to zero slowly after you shut off the engine.

There is an outlet valve/check valve in the fuel pump that should stop drain back through the pump. I told you how to check that valve when you do the pressure check. From what you are saying I would be very suspect of that valve but I would do the check according to the book.

 

Hi Seal,
I just connected a tee in the place where the fuel filter was. With the engine running the pressure gauge did not read any thing. It stayed at zero. I'm not sure though if the gauge I used is what you have in mind. I took the gauge from a small air compressor I have. It reads in psi from 0-125. Perhaps it isn't sensitive enough? I would think at 8 psi it would show, but maybe not at the lower 2.5 psi you mentioned? Is there a more specific gauge you might use.

When I mentioned fuel poured into the line leading from the fuel pump, the gas disappears at a rate of about 1/8 inch per second, and completely disappears. It seems to be all draining back into the fuel pump.

If I disconnect the fuel pump inlet and blow into the fuel pump outlet, will the check valve you spoke of stop me from blowing through the pump to the fuel pump inlet?

Is there a chance these after market fuel pumps are reconditioned and could fail to stop the fuel leak back I'm seeing. If I install a new fuel pump a second time, will blowing through it backwards tell me for sure that the pump check valve is doing what it is suppose to do?

 

I have never tried to blow back through a fuel pump but I would think you should not be able to. Go to the parts store and order a pump at the counter and try it. If you can't blow through it buy the pump, if you can we will all learn something. A 0-125 gauge is fine for an injected engine but not sensitive enough to run a carb fuel pressure test. A gauge will cost $7.00-10.00 and a fuel pump will cost $20.00.

The thing that bothers me here is if the check valve is faulty where is the fuel in the carb bowl going? The fuel in the bowl should be enough to start the truck. You may have more than one problem here. You may have a problem with the pump and the carb. Just something to think about.

 

-"Are you seeing any wet spots from leaking fuel anywhere?"

Is this my problem right here (see picture):

http://pic.atpic.com/2354566

Is fuel leaking from the bowl causing this around the throttle shaft and the base of the carburetor?

Or, is this fuel showing up after it leaves the bowl?

Is there a seal or gasket that will solve this?

 

That picture appears to show the leakage that happens as the throttle rod/hole wears. This is normal and is not repairable. This leak is not the cause of this problem but you might see benefits from a replacement carb and indeed a different carb may or may not solve the problem. Bowl leakage can be internal to the carb and therefore may not be seen. As I have said before you may have more than one problem here.

 

Seal,
I have to thank You and others who chimed in here. Your input was and is very much appreciated. My Dad would always say "You are both a gentleman and a scholar." I'll let you know if I get anywhere with this problem.
Thanks Again,
Les Carlson
Minnesota