350B John Deere crawler

Anonymous-0

Well-known Member
I have a 350B diesel crawler, I was pushing dirt then all at once, it went to less than half throtle. I changed fuel filters and it ran fine for about 5 min. and went back to less than half throtle. I have taken the fuel supply line and the return line off and made sure there was no obstruction. I have replaced the primary pump and am running out of options. I"m hoping someone can help with an idea and not get into the injector pump. I appreciate any ideas.
 
this is usually a fungus problem, where a black slime grows between the diesel & the water in your fuel tank. It clogs up the fuel line where it leaves the fuel tank, the line itself (must be blown out) & the entrance to the fuel filters or the filters themselves. Tank, lines, everything including the filters you just put in, must be cleared or changed. Water should be drained from fuel tank occasionally & you can buy fluid to put in the fuel to keep the fungus from growing. Usually only a problem in machines that are used infrequently.
 
Mine did that when the return line had problems. There is a small glass ball in the fitting that comes out of the pump and you will probably find small black specks in it. That is a part in the pump failing from what I understand. Before I knew what it was, I broke the glass ball out & it ran fine tho a little rough at idle. I don't reccommend that, I do recommend getting in touch with Dieseltech on this forum & having him rebuild your pump. Keith
 
To see if the pump needs repair try this, have a screwdriver ready to loosten the 2 timing cover plate screws while engine is slowing down. If speed picks up and will accelerate OK while fuel leaks out past gasket pump needs repair. Weight retainer ring is failing, blocking the return fitting. Don't knock the ball out and think all is well. After awhile retainer pins will break, locking up the head and break the drive shaft too. What I can fix now just became much more cost and work.
 
The return fitting you removed is the housing pressure control fitting. Removing it will help engine run better IF it is plugged with small bits of broke retainer ring. I like to test by letting fuel leak out at the timing cover for a quick check. Have even loaded tractors on the trailer this way that would die, then haul them to the shop. It may run OK for awhile with it out, but you will have much more damage later if pump needs repair and doesn't get it.
 
Listen to Dieseltech. I DO NOT reccommend removing the ball & driving it that way. I did to get it running long enough to get it back home. This was about 5 years ago and I had it rebuilt. Trust me, Dieseltech will do you a good job at a reasonable price. He has done an injector pump for my Massey 255 and has done several for others on this site. Keith
 
OK, we have blown the supply and the return line out. We changed the filters again, then we loosened the three screws on top of the pump (the piece that the return line comes out of). the engine just barely reved up as the fuel was leaking out of the box. No change in the way it runs. Any other ideas?
 
Remove the top cover, look inside for any small bits that look like coffee grounds. If there are any pump needs repair. If not, check the metering valve at the rear inside for free movement, it may be sticking, not turning on as it should causing low power. It must move freely, move it back and forth and see if it helps free it up if sticky. Any water in fuel can cause it to stick. If pump has electric shutoff be careful that shutoff arm is in front of black arm boss when replaced. To be safe, use a separate ground jump wire on other cover post and set straight down with key on holding stop arm in. If done wrong engine may run away when started.
 
Hey dieseltech, I didn't make it out to tinker with the dozer this evening, but I will do my best to get out there tomorrow evening. However, I was wodering what state are you in (for shipping purposes) and approximately how much is average to rebuild one of these pumps?
 

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