Kohler K91 governor

[Drumnagorrach 9]

not having a lot of success getting the governor, on the K91 fitted to my Allen scythe ,to control the revs  .

I have a download of the manual ,but would appreciate any tips in getting some control of the engine speed .

 

[Wallfish 698]

Set the governor arm according to the manual. With the bolt loose, move the arm away from the carb to hold the carb butterfly wide open, grab the rod with pliers and turn counter clockwise until it stops, tighten bolt to hold the arm on the rod in that position.

When you start the engine and have it running, manually open the carb butterfly with your hand and you should feel the governor arm pushing back to try and close it.

The throttle cable connection to the governor arm must use a spring and not be a direct connection. It's the spring which allows the governor to move and therefore control the carb.

[Drumnagorrach 9]

Thanks , did it as you described and the governor is working , it just hunts after the governor opens the throttle after a high load . I have fitted an extra very light spring to close the throttle butterfly as used on Briggs and Stratton lawnmower engines , seems to help .

bigger Kohler engines seem  to have a more sophisticated system which is easier to adjust .

[Wallfish 698]

RPM Hunting is typically caused by a fuel mixture issue. Mostly a lean condition. With the engine running, adjust the choke closed slowly to see if you can smooth it out to run at a consistent RPM. If it smooths out by using the choke, there is too much air flowing into the fuel mixture causing the hunting condition. Here are some things to check.

Carb high speed or low speed needle adjustment

carb float adjustment

dirty carb, clean it thoroughly, all passages including the little holes in the high speed needle valve

worn butterfly shaft sealing. The sealing where the shaft exits the carb on the top is worn and allowing air to flow in

gasket to the engine

To check the butterfly shaft and gasket spray some carb cleaner around those areas with the engine running. If the rpm changes--- the carb cleaner is being sucked into the carb and therefore there is an air leak.

 

 

 

[Drumnagorrach 9]

Thanks for your reply , I have noticed that the hunting is worse when the fuel tank is low . The operating position on an Allen Scythe isn’t the best ,  don’t know how familiar you are with the machine ,the engine is tilted to the output shaft side when mowing and the fuel tank is barely higher than the carb .I will take the carb off and thoroughly clean it out just in case something is blocked . The low speed jet is fine , the engine starts first pull of the cord when warm and fires on choke when cold but the choke has to be opened immediately for the engine to keep running . Low jet  is set at 1.75 turns out .

high speed jet is set 2 turns out .

 

[Wristpin 400]

Not just the tank level that is iffy but the fuel in the carb bowl is going to be well out of kilter as well.

[Drumnagorrach 9]

And yet, this is how the engines were fitted from the factory on later model Allen Scythes, mine was re engined with the later Kohler , originally a Villiers two stroke .