850 Deere developed a knock

deene

Member
A few weeks ago i asked about the injection pump not working on an 850 deere. It stopped pumping fuel on number 2 injector, i found place to rebuild it and 1500
dollars later its back on and purged. i started it up today and bled the lines and got it running on all 3 cyls, pulled it out of the shed and engaged the finish
mower, made it about 100 feet and it developed a knock.
Frustrated to say the least but wondering about causes, it went back on with the same 2 shims that were there when removed, i am wondering if it running on just 2 cyl
messed with something, if this might be worn cam bearings allowing it to knock now that all three plungers are operating up to par, or if it was just an opportune time
to lose a rod bearing. It started and ran perfect in the shop at all rpms and i set the linkage to run lower than advised high idle because we just use it to mow so
dont need full rpms for that,any thoughts, i first thought about timing knock like its to far advanced but dont know why it wouldnt do that while running in the shop
but know it does it whenever i start it up.
 
A failed injector can cause a knock. (Bad spray pattern or low pop pressure.)

Being carefully not to get fingers, etc. where they could get sprayed/penetrated with diesel fuel loosen the injector lines one at a time and note at which cylinder the knock stops or lessens.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top