Cub Cadet 125 - governor issue

dhermesc · Jul 23, 2018

The cub worked fine last year. This year the governor won't kick in when under load. At first I thought it was down on power but after spending some time on it I realized the governor just wasn't kicking in at all. The governor arm moves freely and I tried different spring combinations with the throttle but no change. Where do I go from here?

Bob · Jul 23, 2018

If the governor is regulating speed (in other words not allowing the engine to "run away") it's working, at leas to some degree.

As you know, spring is trying to yank throttle butterfly "open", force from the governor weights being thrown outward by centrifugal force acts against the spring to try to close the butterfly.

If governor breaks/throws weight(s) there's no counteraction to the pull of the spring and engine will run wild.

You can verify that the lever position on the governor shaft/linkage length are correct by noting if throttle butterfly shaft reaches its "wide open" stop" JUST before the governor lever reaches the end of it's travel in the "WOT" direction.

That also verifies that the governor weights are not somehow stuck and are able to fully retract in the direction that go when the engine slows under load and the carb butterfly needs to be opened a bit to compensate.

If that is correct, I would say you have some sort of low engine power issue... not getting enough gas, plugged air filter or, maybe the meeces plugged the muffler with dog food chunks!

Also, check ignition timing with a timing lite.

dhermesc · Jul 23, 2018

It is regulating top speed but does not "kick in" at all once load is applied. I will look into the other suggestions tonight. Thanks!

dhermesc · Jul 24, 2018

Muffler is half clogged with mud dubbers. Pulled the head and the exhaust valve is not seating.

DR. EVIL · Jul 25, 2018

At what engine RPM are you checking and saying the exhaust valve isn't sealing? A K301 engine in a 125 CC has "ACR", Automatic Compression Release, there's a centrugally operated finger recessed into the exhaust valve cam lobe that bumps the exh valve open .050" early to allow the starter to easily crank the then over top dead center on compression stroke. Once the engine gets up to 400-600 rpm the centrifugal mechanism retracts the finger, it lowers below the surface of the cam lobe. Be careful with that finger, it's heat-treated sheet steel, very brittle. You can adjust it slightly once, maybe twice.

The Kohler K-series engine manual is available free on-line, whole chapter on ACR, Also the IH Cub Cadet Operators and service manual have good information about working on the Kohler engine. You can find the IH manuals free on IHCubCadet.COM.

Cub Cadet 125 - governor issue

dhermesc

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Bob

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dhermesc

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dhermesc

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DR. EVIL

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