My Tractor Forum banner

Kohler Magnum M18 Slow Governor Response

3K views 5 replies 4 participants last post by  dave_r 
#1 ·
I have an Ariens GT with a M18. today while snow-blowing it started to over rev when coming out of a load on the engine. It would rev high for a couple seconds an then come back down to normal. Been running fine and started this today did it about 5 or 6 times.

Haven'y really looked at it yet just wondering where to start. Tractor has pretty much run flawlessly for the 10 years I've owned it.
 
#3 ·
The governor works on the external linkage. If the external linkage does not have any binding, and moves freely, then it should respond to the governor trying to close the throttle plate.
OTOH, if the governor internal bits are sticking, it would not pull the throttle closed, and you would/could have over-revving occur.
I would move the external linkage manually to determine if there was any position where wear or corrosion or ??? could cause it to stick. If it moves freely, then likely the problem is internal. Be sure that the throttle plate is not binding in the bore when moved to WOT. If the screws retaining the plate were to loosen, it could move internally, and cause the throttle to stick intermittently. Time for a couple inspections..
The governor arm should also move freely when the engine is off. You should be able to move it such that the throttle goes from idle to WOT without problems. If it binds, well you can figure that out.
Though the governor is bathed in engine oil whenever the engine is running(if it is not submerged when not), it still can have wear on its moving parts. If it has plastic parts, they can wear, and also become brittle with age and multiple heat cycles along with soaking in hot oil whenever in use. If it binds, I would be careful when running until I could take it apart and inspect the governor bits.
tom
 
#4 ·
The governor works on the external linkage. If the external linkage does not have any binding, and moves freely, then it should respond to the governor trying to close the throttle plate.
OTOH, if the governor internal bits are sticking, it would not pull the throttle closed, and you would/could have over-revving occur.
I would move the external linkage manually to determine if there was any position where wear or corrosion or ??? could cause it to stick. If it moves freely, then likely the problem is internal. Be sure that the throttle plate is not binding in the bore when moved to WOT. If the screws retaining the plate were to loosen, it could move internally, and cause the throttle to stick intermittently. Time for a couple inspections..
The governor arm should also move freely when the engine is off. You should be able to move it such that the throttle goes from idle to WOT without problems. If it binds, well you can figure that out.
Though the governor is bathed in engine oil whenever the engine is running(if it is not submerged when not), it still can have wear on its moving parts. If it has plastic parts, they can wear, and also become brittle with age and multiple heat cycles along with soaking in hot oil whenever in use. If it binds, I would be careful when running until I could take it apart and inspect the governor bits.
tom
The governor on this engine opens the throttle valve under load. It does not close it. If the engine is over reving the governor stop are either out of wack or the linkage is binding some where on the outside of the engine that is not allowing the throtle to close when the load lightens.
 
#5 ·
Well it turns out after finally getting a chance to look at it, that the screws holding the Intake elbow to the carburetor had worked them self loose.and had it it essentially had fallen off. Which allowed the governor linkage to go all over the place. Put it all back in place an d tightened the screws and we are Hunky Dory.
 
  • Like
Reactions: dave_r
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top