Sudden high RPMS!

[PatS]

I was using my CK20S gear tractor today, backing up when suddenly the engine began to go at high RPMs (over the redline).I had the clutch in so I didn't move. I turned off the key but that did nothing. Finally, I popped the clutch and the engine died. This was probably 20-30 seconds of high rpm Black smoke was pouring out while it was revving. I opened the hood and looked around. A headlamp that you wear on your head with elastic strap was lying between the the battery and radiator. It is all plastic. Finally started it it up and it seemed to run fine but I was done for the day

Any idea what caused this?

Will it happen again?

How much damage was likely done to the engine?

Should I change the oil?

Thanks for any help

 

[o2batsea]

It's called "running away" it happens when the engine begins to fire off the lubricating oil.
If stopped soon enough it usually is harmless. If you can't stop it it can blow the engine.
Was the oil over filled?

 

[PatS]

t seems to be running okay now. Last I checked the oil it was okay. Is there a way to prevent it?

 

[IslandTractor]

Something like this happened to me once and it was caused by a stick I backed over that popped up and jammed into the throttle cable. However, unlike a runaway engine, I stopped it with the key.

 

[JoelD]

Yes the not stopping with the key is odd

Are you certain you turned it off?

If you did I'm thinking the would've cut the fuel sorce and if so that would mean you had a different fuel source going

Could be the headlamp jammed up throttle linkage but that would not explain key not working

 

[MotorSeven]

Pat...new tractor or used?

 

[Coyote machine]

FWIW, check out recent post about CK-30 sticking throttle. It may not solve your problem, but it's wise to make sure the linkage and cable have enough lube.
Hope you find the source of the issue and are able to prevent future instances of it.:thumbsup:
I'd check all your wiring- complete harness to make sure there are no electrical problems like shorted wires, etc. The ignition switch is suspect too until you can eliminate it as a possible tie in to the problem.

 

[PatS]

Thanks for the feedback. I'm sure I turned the key off, several times. I wonderd if there was a short somewhere, but could that cause the high rpms? The "running away" mentioned by O2batsea seems plausible. It was like it was running away out of control. I got it used a month ago, has 223 hrs. There doesn't seem to be a kill switch. Would that stop it? It seems to be running normally now, but I imagine even 20-30 seconds of very high rpms did some damage or caused excessive wear of piston rings or other parts.

 

[JDL538]

I doubt very much if 20 or 30 seconds would have done any damage.

 

[DanD78]

Gas vapors in the air will make a diesel engine run away where the key will not shut them down. Propane or natural gas leak, gas vapors, laquer thinner vapors. That's why some use either to start a cold engine. May not have been your issue but FYI.

Dan