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Hoof Governor

PostPosted: Tue Feb 18, 2020 8:01 pm
by FarmerDick10
Can anyone explain how a Hoof governor works? I have one on my R-170. I had it rebuilt at a carb shop, but do not quite understand the principle behind it.

Re: Hoof Governor

PostPosted: Tue Feb 18, 2020 9:14 pm
by nikkinutshop

Re: Hoof Governor

PostPosted: Tue Feb 18, 2020 9:18 pm
by cornbinder89
Are you talking about a belt driven gov or a velocity gov or a Centravac gov?
Belt driven is fairly obvious
Centra vac has a control on the distributor to close the throttle when the speed is reached
Velocity gov limits the total air flow thru the intake. It is the least accurate gov.
Hoof made belt driven and velocity types.

Re: Hoof Governor

PostPosted: Tue Feb 18, 2020 9:20 pm
by Binder Mike
I was hoping it was something leftover from the horse and buggy days. :mrgreen:

Re: Hoof Governor

PostPosted: Wed Feb 19, 2020 7:23 am
by FarmerDick10
it is a velocity governor that sits between the carb and intake manifold. there are no mechanically driven parts, and no external levers or cables.

Re: Hoof Governor

PostPosted: Wed Feb 19, 2020 7:45 am
by cornbinder89
A throttle plate (or plates for a2bbl) are mounted on a offset shaft such that air flow thru the gov will try and close the plates, a spring tries to hold them open, when air flow exceeds the spring pressure they start to close, limiting the power and therefore speed of the engine.

Re: Hoof Governor

PostPosted: Wed Feb 19, 2020 3:31 pm
by FarmerDick10
Thank you very much. This really helps me understand it.

Re: Hoof Governor

PostPosted: Wed Feb 19, 2020 5:42 pm
by cornbinder89
I may have over simplified a bit, but that is the basics of how they work. As I said, they are the least accurate of the governors.
Belt driven will hold speed ok but if the belt breaks, look out! They aren't a max only set up, but used to control the engine to a set speed.
The centra-vac set up can be used to max only or can be used for setting the engine speed for PTO like they did with the elect-rall generator that someone on the board restored.

Re: Hoof Governor

PostPosted: Thu Feb 20, 2020 6:33 am
by FarmerDick10
I am familiar with the governors used on farm tractors and industrial equipment. I have never seen one like this before. It has a maximum rpm stamped on the cover plate so I guessed that it was used to control maximum speed of the engine. It is on a dump truck which I presume was designed to work with multiple operators, some of which might not be trusted to take care of their machinery. What I did not understand is how it could possibly work without some sort of external linkage like the ones used on farm tractors.