Engine stops running at a half tank

[retiredtoy]

My M35A2 1971 runs and starts perfect. I always keep the fuel tank full. I am selling it and decided that I should not let a full tank of fuel go with it. I took out 30 gallons, started the engine, drove about a 100 feet and the engine died and would not restart. I put 15 gallons back in it. (this raised the level to a half of a tank. The bubbles stopped flowing in the fuel lines and it started.
I wasn't sure if this was problem so I drained out 10 gallons. (Really didn't want to give al that away.) It ran about 2 to 3 minutes and stopped again. Refilled to half tank and it runs again.
Can someone tell me what I need to do to repair? I don't want it selling without being repaired.
Your help will be very much appreciated.
Thanks John

 

[eagle4g63]

Pull the fuel pump assembly, may have a hole in the line or something like that.

 

[goldneagle]

My M35A2 1971 runs and starts perfect. I always keep the fuel tank full. I am selling it and decided that I should not let a full tank of fuel go with it. I took out 30 gallons, started the engine, drove about a 100 feet and the engine died and would not restart. I put 15 gallons back in it. (this raised the level to a half of a tank. The bubbles stopped flowing in the fuel lines and it started.
I wasn't sure if this was problem so I drained out 10 gallons. (Really didn't want to give al that away.) It ran about 2 to 3 minutes and stopped again. Refilled to half tank and it runs again.
Can someone tell me what I need to do to repair? I don't want it selling without being repaired.
Your help will be very much appreciated.
Thanks John

Maybe you have a hole in the rubber hose inside the fuel tank or the hose is off the pump connection. Just take the whole assembly out and check it.

 

[eagle4g63]

^ I must have just pushed the button a split micro second faster than you

 

[goldneagle]

Pull the fuel pump assembly, may have a hole in the line or something like that.

2 eagles think alike!

 

[eagle4g63]

^ twice now, I hit enter and both our posts go up!!!

 

[hoop]

And you have your answer.

 

[73m819]

WEB SITE HELP is for problems WITH the WEB site, NOT truck troubles

 

[Flyingvan911]

Yep. This thread should be in the deuce forum. And ditto on having a hole in the hose in the tank. It isn't hard to fix. Just be sure the hose you use is diesel proof.

 

[Ridgerunner]

I've seen the bottom of the in tank fuel pump fall off before. When this happens and the fuel is higher than the bottom of the broken pump, the injection pump can pull fuel and continue to run. Once fuel drops below that point, the IP starves for fuel and the truck quits running.

 

[klmartin62]

If the in-tank pump has been replaced previously, the hose connecting it to the pick-up tube can be loose, (not tightened properly) causing it to bypass when the weight of the fuel around the connection is reduced. I have run into this often.

 

[retiredtoy]

Thanks to you all

I will learn someday to check out the whole site before posting in the wrong place. Sorry
I think the bottom falling off the pump is the closest thing yet. I has to be something about the intake of the pump because it is sucking air into the system. Bubbles flowing through the white plastic lines.
I will take the pump out tomorrow morning.
I thank you all for your help.
John

 

[retiredtoy]

Well Ridgerunner, you were pretty close to what the problem was. When I removed the pump, I noticed that it looked short. As you know Ridgerunner, there are two long brackets with holes down the sides. Someone had apparently pulled this pump and found that the output pressure hose was leaking. They cut off the bad end, moved the pump up the bracket holes about 4 inches and replaced the pump. The inlet screen for the pump was then at a little above half tank.
Again thank you all.