Govenor

[Williamb]

So I can start my Cub but have no throttle control. With the engine off I can move the throttle linkage and it seems to move the carb connection. With the engine started the throttle does nothing. I tried lubricating all the external parts but don't relish taking off the governor. I'm not sure what I should do to externally adjust the throttle. The spring at the governor doesn't seem to have much tension perhaps the linkage should be tightened?
Any ideas from a real mechanic appreciated.
Thanks

[MiCarl]

I haven't seen your particular problem but do have some thoughts about diagnosis:

First, since things move with the engine off lubrication/sticking is probably not your issue.

When you move the lever on the steering post you pull on that spring and the spring in turn pulls the throttle open and moves pulls the governor weights in. When the governor is spinning the centrifugal force of the spinning weights works against the spring to push the throttle closed. The balance between the spring tension and centrifugal force is what keeps the engine at a constant speed.

Of course when the engine isn't turning there isn't any centrifugal force and the throttle will snap wide open with little lever travel.

For some reason the weights in the governor and their centrifugal force is overcoming the spring tension. The lever the spring attaches to is known to break. I'd inspect it for any cracks. If it looks good I'd double check where the spring attaches at both ends and make sure it's installed properly.

If it all looks good I'd replace that spring before doing anything else. Make sure you get the right spring for your tractor. There were at least two different ones and I'm not sure off hand which goes to which model of tractor.

[Glen]

Hi,
You didn't say what year the Cub is.

Below is a pic from TM Tractor of the governor housing with the spring, you can see if yours looks the same. They need oiling where the cotter key is, they can get tight on the pivot there with no oil.

Below is a listing at TM Tractor for a new governor spring.

http://www.tmtractor.com/new/gv/357fp.htm

I sent you a PM.

[Ruralguy57]

I do have some idea of what may be happening here. On my Cub, the throttle was frozen. The people who sold it to me only used the choke to control how it operated. The only movement when using the throttle control the arm was it bowed and that was it. Is it possible that the throttle arm is rusted tite on the throttle shaft pin, and only moves maybe 1/2 inch or less forward or backwards? Once I loosened up the two, and the throttle seemed to work easier, back and forth on the notches on the throttle plate, I then had to look at the arm that connected the shaft of the carb to the cross over arm of the governor on the left side of the tractor. There is a "U" shaped hasp that is held together on the threaded shaft with a lock nut and pin and cotter key. My Cub would not run evenly. In fact it bellowed....ran up and then down and up and down and then eventually shut off. In my case, I had to adjust that hasp. I worked the throttle to the max and minimum while adjusting the hasp. Once that range was achieved in the notches, [note: I moved the hasp toward the seat first then I had to move the hasp toward the radiator] and the hasp was adjusted the tractor ran fine. You may have to loosen the throttle shaft that could have been rusted on the pin as it was on my Cub. [I am not sure if techniques on loosening are allowed in discussion] I also took out the carb and blew it out with air with out separating the carb and replaced it. I hope my trials helps you with yours.


Richard

[Glen]

Hi,
Richard, that is a clevis on the throttle rod, ahead of the carburetor, the Cub and LoBoy parts manual calls it.
It has to be adjusted to the right position, so the governor will work right.

[Ruralguy57]

Glen, you are so right....

I agree...300%....the Cub will not run well if it is not. I fought it for several days prior to adjustment!


Richard

[inairam]

99% of the time problems are in the throttle to governor and or governor to carb linkage. 1% or less of the time it is the governor. Exhaust all other possibilities before messing with the governor itself. I have had throttle stick to shafts. The rod from the throttle to the governor in backward so it binds, the lever on the governer frozen to the shaft spring broke or weak, shaft to carb frozen, rust on the shaft end going to carb binding throttle linkage.

There are a number of things that a little sandpaper and oil are very easy to fix.