John Deere F935 engine trouble

dlbcheckmate · May 17, 2009

Hello, great site ! I have a John Deere F935 with a Yanmar Diesel engine. I rebuilt the engine (new pistons, bearings, rings, injectors, glow plugs ect) after it started ok, I ran it about 1/2 hour ( mowing) or so and it quit under load. I was able to restart it after bleeding but it does not seem to have full power and really doesnt seem right. When I crank the engine over to bleed the fuel system it will actually slow down and almost stop cranking when you crack the #1 injector line when you tighten up the line it resumes cranking ? Any ideas ?

Kyle_in_Tex · May 17, 2009

Why did it need rebuilding in the 1st place?

Hope it's not overheating. Can't say for sure but is the injector timing good?

dlbcheckmate · May 17, 2009

I bought it from a surplus dealer, it had sat for a long time. Found one rod bearing gone and the crank journal bad. Repaired the crank and installed the new parts in the engine. I did not check the injector timing after reassemble, but it seemed to run great on the initial startup?

zzvyb6 · May 17, 2009

Did you replace the fuel filter? It has a water detector and may put a light on if it senses water. Mine acted just like yours until I replaced the fuel filter. Also, if yours has dual tanks, the fuel gage switch reads the tanks but the "other" lever actually switches the tank manifold. This can result in a great loss of scalp hair. Make sure your fuel pump is clicking while you are at it. This is a really nice lawn mower. I have the 72" deck and cut a couple of acres in 40 minutes (lots of trees to go around). I put Gator blades on it and some aggressive ATV tires for hill climbing. I even added headlights for night cutting... There's a few other things to check if this doesn't help. I'll have to have a Red Bull in order to remember what all I did. Seems there was an air intake full of a mouse nest or something similar.

dlbcheckmate · May 20, 2009

Well, I checked the timing tonight and it is WAY OFF. I have a single shim .020" in as the manual describes but my timing mark is at least an inch off? I pulled the pump housing off and it looks normal no major wear or broken parts. Could I have misaligned the timing gears when I reassembled the engine? I checked the timing twice before pulling the top. I don't want to pull the engine out if I don't have too. Thanks

Dave

dlbcheckmate · May 24, 2009

any ideas before I pull the motor again?

Wis Bang · May 24, 2009

dlbcheckmate said:
Well, I checked the timing tonight and it is WAY OFF. I have a single shim .020" in as the manual describes but my timing mark is at least an inch off? I pulled the pump housing off and it looks normal no major wear or broken parts. Could I have misaligned the timing gears when I reassembled the engine? I checked the timing twice before pulling the top. I don't want to pull the engine out if I don't have too. Thanks

Dave

Is it possible to be 180 degrees off?