John Deere diesel problem

[MFalkinham]

I was mowing with my John Deere 332 yesterday (16hp Yanmar 3cyl, 700 hours), when it suddenly began running very rough like one cylinder wasn't working, and had a loss of power. When I tried to shut it off, the engine went into runaway and wouldn't shut off. I was finally able to start it up again and then shut it down. I tried changing the fuel filter (which didn't look that bad), but after a couple of minutes of normal running the problem returned.



I talked to the JD mechanic who sold me the tractor 5 years ago (it was his personal unit, but he upgraded to a 400-series), and he thinks it might be a bad injector, and not the injector pump. Does this sound correct, or what else might it be? He is coming to pick it up today for troubleshooting and repair, but I'd like a second opinion.



Thanks!



- Mike

 

[fox]

A bad injector can make it run rough. Either stuck open or closed.

An injector problem won't cause it to go into a run away condition.

When you shut it off, did it rev up or just continue to run?

Is there oil in the air cleaner or intake?

 

[MFalkinham]

I agree that a bad injector should not have caused a runaway. While the runaway happened, the engine speed slowed quite a bit. No oil in the air filter, although it is at the end of a curved rubber hose, so maybe oil wouldn't make it that far.



He mentioned that it might be a bad solonoid that shuts off the pump. I'm waiting to hear from him what he finds.



Thanks again.



- Mike

 

[lschultz]

Keep us posted. You never know when one of us might have this problem.

 

[MFalkinham]

Update... .



Of course, the problem didn't happen for the mechanic (he didn't have the mower deck, and couldn't put it under full load), so he put some injector cleaner in the tank and told me to try it again. It acted up under load after 15 minutes of mowing, so I began troubleshooting it myself. I tried overriding several possible points of mechanical failure, but the problem continued.



On a hunch, I drained the fuel tank and refilled it with fresh diesel. The engine immediately started running better. That's when the truth finally came out. Turns out that while I was away on a business trip, my brother-in-law tried to doing my wife a favor by mowing our lawn. Apparently, he had trouble figuring out how to operate the tractor, so he gave up and drove it back in the garage. How much do you want to bet he accidentally topped off the tank using the RED can??



My guess is that gasoline and diesel fuel must separate in the tank when sitting, and during 15 minutes of running they become mixed together. The tractor is running much better now, and my family members have lost their tractor privileges. But I still wonder about long-term engine damage of running diesel fuel contaminated with gasoline for two hours.



- Mike

I was mowing with my John Deere 332 yesterday (16hp Yanmar 3cyl, 700 hours), when it suddenly began running very rough like one cylinder wasn't working, and had a loss of power. When I tried to shut it off, the engine went into runaway and wouldn't shut off. I was finally able to start it up again and then shut it down. I tried changing the fuel filter (which didn't look that bad), but after a couple of minutes of normal running the problem returned.

 

[bmoeller]

Fuel injection system would be the main concern from poor lubrication.