VAC Governor function?

mmaki · Oct 20, 2013

I am putting back together my VAC (my first tractor) and I am a little confused as to what the governor is suppose to do and how to adjust it.

I think that the function of the governor is to maintain 1450 rpm under load. If that is true, then is there a slower idle speed? And if the governor is always controlling the throttle, then what is the purpose of the foot throttle and the dash hand throttle?

Thanks,

Mike

1031D · Oct 20, 2013

The governor is not designed to make the engine run at a certain speed, but it is designed to help the engine maintain a certain speed. The throttle shaft and governor spring help the engine run at a certain speed. For instance when you go out plowing, and you pull the throttle down all the way, when the tractor hits a tough spot it will automatically speed the engine up to maintain wide open throttle

Christopher Mikesell · Oct 20, 2013

The foot throttle and hand throttle both adjust the tension on the governor spring. This spring is mounted externally, and the tension can be set to give a governed RPM anywhere between 450rpm and 1550rpm. You can also set the governed RPM higher, but your fuel efficiency will suffer and things will wear more quickly. Also, the governor is not perfect at maintaining RPM. Thus, you can expect small decreases in engine speed as the load increases. Also, increasing the load excessively will cause the engine to lug.

DKase · Oct 20, 2013

The throttle sets the engine speed. The governor does its best to maintain that speed under load changes.

olddog · Oct 21, 2013

It's purpose is to keep a narrow RPM range.
The early VAC had a ball/ramp type, the later were a flyball type.
Your foot is attached to a spring(s) that is trying to open up the carbatooter.
The governor's job is to push the R's down (when rev's go up), obtaining a balance against the spring(s)on your foot.
Removal of the governor will likely ventilate the block on most any color tractor.

mmaki · Oct 21, 2013

Thanks for the responses.

Should the governor have a spring action? Mine just flops back and forth with no return to idle. Or does the spring action develop with the engine running?

I understand the foot throttle pulls the governor through a spring, but what is suppose to close the throttle?

Christopher Mikesell · Oct 21, 2013

The governor only pulls against the throttle spring (to close the throttle) when the engine is running. It works by centrifugal force.

olddog · Oct 22, 2013

Chris answered quite rightly..... the governor only works when the engine is running. Engine off, throttle at idle, it will flop around.
Make sure you check the little needle bearing for the rockshaft in the front cover. By now, most of them are gone or at least rusted.

VAC Governor function?

mmaki

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1031D

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Christopher Mikesell

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DKase

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olddog

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mmaki

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Christopher Mikesell

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olddog

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