Fuel returning to tank m35a2 1971

[Daximus]

Im new to the site. I just bought a 71 m35a2 deuce and a half last week, i dont have much knowlege on a deuce but i have some experience working on semi trucks, the truck had been setting for awhile got it home, drained all the old fuel out was mostly used motor oil and cooking oil, put about 25 gallon of fresh diesel in the tank drained the fuel filters and filled with fresh diesel. We had the truck starting acouple of time it would run for about a minute or so but will not stay running.

The problem im having is most of the fuel is going back into the tank on the return line, i removed the injector lines and plugged the return line and turn the switch on and started cranking on it and it was pumping fuel out the hydralic head, it had clean fuel pumping out, so i hooked the return line back up to the tank and cranked on it again and it would bearly spit any fuel out the hydralic head.

If anybody has any idea or knows what it is im all ears.

 

[fsearls92]

Start with changing the fuel filters

 

[Tracer]

First welcome aboard. Second, as already stated change you primary and secondary fuel filters, and check your fuel tank for debris. Also get familiar with the TMs (tech manuals). You'll find plenty of knowledge and support here. Keep us posted on your progress. (send pictures)

 

[Daximus]

Thank you, i have a primary filter just waiting on the two secondary filter to come in suppost to be tuesday and ill update on it

 

[m715]

After you change the filters, if you still do not have fuel flow at the hyd head check the button. Search here for info .

 

[Floridianson]

As said get all three filters changed. Then what we are looking for is fuel pressure when the in tank is running. If we want to check pressures then we put a gage between the secondary and final fuel filters. The correct pressure with in tank should be 4lbs. In most cases if it comes out when you open the bleeder you most likely have 4 lbs. and you know your in tank is working. With the Deuce motor there is never a need to remove injector lines to bleed or watch for fuel. If you remove the line from the final filter at the Head and you have fuel running there then fuel delivery to head is not the problem. From there we would go to the fuel control assembely under the shut down cover. The fuel control should move free with your finger and with the motor off it should look like it is sitting at the seven oclock position. With you finger it should easy go back to the four oclock position then snap back to seven. If that is free then we might think about the button if we had a no run problem. You said yours would run so I do not believe the button is your problem as of yet.

Wish they would make it a sticky that the way our multi fuel motor is set up there is NEVER a need to crack injectors to remove the air. They will self clear.

 

[rustystud]

Wish they would make it a sticky that the way our multi fuel motor is set up there is NEVER a need to crack injectors to remove the air. They will self clear.[/QUOTE]

That was a clever design they used on the injection pump. Sure beats trying to get prime in a combat situation !

 

[Daximus]

update on the deuce i put all three new filters on it and it is still no start, i have already checked the shut off is at the 7 oclock and moves freely.

 

[Floridianson]

Do you have fuel at the bleeder between the secondary and final. If I know the filters are new and I get some fuel coming out of the bleeder then I don't even bother taking off the fuel line to the head. These motors/trucks if there is fuel to the head then they run or we have other problems with the head. If you have fuel to the head and no one has messed taking out the IP then we look to the button if fuel control is free. You said yours is free so Huston we have a problem.

 

[Eliteweapons]

I don't have any experience on the multifuel but I noticed you said it had old cooking oil as well as waste oil. Could the cooking oil have solidified in the pump or injectors?

 

[bonedoc]

Unplug your return line. If your in tank pump is working properly you will have a constant stream of fuel coming back to the tank as it runs.
As others have said. Change the filters, start there. Does it only idle for a minute or if you give it some pedal will it stay running. As one of the previous posters said no telling what deposits you have in the lines and injectors if it was running waste oil, cooking oil, etc.

 

[frank8003]

perhaps you would read thru this one
http://www.steelsoldiers.com/showthread.php?163387-Rebuilding-the-Injection-pump

There is ways to see what is doing what and when and
the failure modes

 

[gimpyrobb]

Check for fuel at the bleeder first. If you have fuel at the bleeder and it does not start by itself, give it a quick whiff of starting fluid. If it starts and dies, you probably haven't got the filter O-rings on right and are sucking air.

 

[Daximus]

Update on the deuce, i took the hh off and the button was off put it back on and the clip put it back on cleaned out the diesel lines and the truck started drove it about half mile and the clutch was acting like it was disengaged as if i had it pushed in so i turned the truck off, now when i try to start it just the flywheel turns and nlt the engine

 

[cattlerepairman]

Update on the deuce, i took the hh off and the button was off put it back on and the clip put it back on cleaned out the diesel lines and the truck started drove it about half mile and the clutch was acting like it was disengaged as if i had it pushed in so i turned the truck off, now when i try to start it just the flywheel turns and nlt the engine

Did you check that on the starter side? Do you actually see the flywheel move while the engine doesn't turn over? If that is indeed true, open the inspection cover at the bottom of the bell housing....the flywheel bolts should fall out....

The flywheel ring is heat shrunk onto the flywheel, so I doubt that that one is loose.

People have reported loose flywheel bolts before - usuall as an incidental finding. I am not aware of a "free wheeling" flywheel, yet.

 

[Daximus]

Yes i took off the inspection cover hit the starter and got under it and it is just spinning, no bolts came out

 

[cattlerepairman]

I do not know if the bolts can back out sufficiently for the flywheel to spin freely without the bolts falling out...maybe not enough clearance in the housing for them to come all the way out. What else can make the flywheel spin freely? Broken crank?

 

[Daximus]

Thats what im thinking is the broke crank domt know how it could of broke but, when i get a chance im going to see if i can spin the engine over with a braker bar on the front of i can im going to take the oil pan off and look see if i can see anything

 

[snowtrac nome]

if you have a diaphragm pressure plate the bolts are in the clutch housing either way likely a need for a new crank and flywheel. my experience is when those bolts come loose it does damage

 

[rustystud]

I don't believe they make a diaphragm pressure plate for the multifuel engine. I've only seen the three and four finger spring plates.