755 Loss of Power

fishmen222 · Apr 26, 2015

Also posted this in the general forum...not sure where it should be. 1992 JD 755 with 820 hours. Ran perfect for five years. Performed first cutting this year, no problem. Halfway through the second cutting, started to lose power and parked it. Replaced air filters, fuel filter, recent hydro change, new fuel after first occurrence. Brakes not binding. Same result. Starts fine, but runs rough. Do I need to pull the tank, or does this sound familiar to someone else as another problem? Thanks a bunch.

pmsmechanic · Apr 27, 2015

My first thought is, what's obstructing the fuel flow from the tank to the injection pump? Take the fuel line off at the fuel lift pump and check to see that there is a good flow.

holzboat · Apr 27, 2015

Have you ever replaced the fuel lines/hoses? May not be the problem but after 23 years it's something to consider.

fishmen222 · Apr 27, 2015

Replaced lines. Pulled pick-up to pull the tank. Pick-up was spotless. Reinserted, re-bled...same deal. It stays at idle running rough regardless of throttle position (throttle cable fine). If it were either pump, I would at least expect a small variation in RPM. Thoughts? Thanks folks.

fishmen222 · Apr 27, 2015

Interesting. I just re-pulled all lines...fine. When I went to re-bleed, both filter bleed screws shot fuel. However, the injection pump screw had almost nothing coming out. Has to be at the exit of the filter casing (new filter), or the inlet to the injection pump. Will bypass the filter tomorrow to determine. Never heard of this.

TimZib · May 21, 2015

fishmen222 said:
Interesting. I just re-pulled all lines...fine. When I went to re-bleed, both filter bleed screws shot fuel. However, the injection pump screw had almost nothing coming out. Has to be at the exit of the filter casing (new filter), or the inlet to the injection pump. Will bypass the filter tomorrow to determine. Never heard of this.

Having same issue. How did you solve the problem?

jdp2011 · May 21, 2015

FYI when you pulled the pickup out of the tank there should be 8 to 10" of plastic fuel line with a fine mesh screen at the end. If it is not there in bottom of tank. The plastic line will rott then break off from the metal pickup tube

jd110 · May 21, 2015

I had one recently with the same symptoms. That one had the three point hitch running in relief. Try pushing the three point lever forward to see if anything improves. Also be sure the joystick for scv is neutralizing itself. If it still runs rough, you might have a bad fuel injector.