CH640 Governor prob. No return. Running the engine. Is this stock?

[BrownCoat]

Hey everyone. Now that I got the Grasshopper actually running I'm thinking that the governor is either broken, missing parts, not adjusted correctly or was installed wrong. I have no way to know what the shop did to this mower before I got involved. They don't keep records and this is my Dads mower I'm trying to fix for him.

The issue is that it seems the only thing controlling the throttle is the governor and not the linkage from the throttle lever. I can push the throttle lever forward and it will connect with the "Governor Arm" and push it forward but that's it. If I move the throttle lever back the "Governor Arm" stays where it is and wont return and seems to want to increase in speed. I have to reduce the engine speed by moving that lever/arm back.

I've attached a couple of pics to help illustrate. The FSM shows that I'm missing a second spring but that spring wont help the Gov Arm to return. I only know the basic premise of what a governor is and what it's supposed to do, but I don't really know a ton about them. Does the first pic look pretty much normal? Or, is something wrong that I can't see/don't know about?

The second pic is what I did to make the gov arm return to closed throttle. Notice I installed a return spring to make it come back to idle. That's a drum brake spring from a Honda XR100 and it's pretty stiff, so I just threw it on to see if it made a difference. It does. I can cut a little "test grass" with it but I have to do the throttle work that the gov would normally do.

I could easily over rev that engine the way it is right now and during my test run I had to constantly adjust the throttle as you might expect.

I guess I need a crash course in Governors or why it would act up. When he put it away last year he could control the throttle with the lever with no problems, so what could have happened since then? Weird.

Once again, thanks in advance.

 

[mechanic mark]

http://www.kohlerengines.com/onlinecatalog/pdf/24_690_06_EN.pdf

 

[BrownCoat]

Thanks for the link. I have that pdf and checked it out earlier. Everything looks to be ok to my untrained eye.

On a side note, I hosed everything down good with PB blaster the last two days just to make sure nothing was sticking or rusted. Things seem to move pretty easy. There is some tension when trying to move the governor arm. Not much.

 

[BrownCoat]

Does anyone have any idea why the governor won't return after you increase the throttle? Everything looks like it's correct when checked against the service manual.

 

[bertsmobile1]

Govenors ether work or they don't work.
The govenor SLOWS the engine down so when at rest the govenor should be holding the throttle butterfly wide open.
When you start the engine the govenor shold be holding the throttle butterfly partially closed.

The most common problem when refitting the govenor is to connect it backwards.
Read the manual carefully several times , draw a few diagrams to get it clear in your head then check your mower.

If the govenor when attached properly does not close down the throttle, it is broken and in need of URGENT REPAIR as little bits fly off and end up stuck in the gears, not good.

 

[BrownCoat]

Govenors ether work or they don't work.
The govenor SLOWS the engine down so when at rest the govenor should be holding the throttle butterfly wide open.
When you start the engine the govenor shold be holding the throttle butterfly partially closed.

The most common problem when refitting the govenor is to connect it backwards.
Read the manual carefully several times , draw a few diagrams to get it clear in your head then check your mower.

If the govenor when attached properly does not close down the throttle, it is broken and in need of URGENT REPAIR as little bits fly off and end up stuck in the gears, not good.

Thanks, Bertsmobile.
Then it's just not working. He'd been having problems with it before, so when it wouldn't run the deck without bogging down he just parked it. After a year of sitting I got to it and figured out the pushrod problem, then that brought me to the issue I'm on now. We never touched the governor the whole life of the mower. I didn't even know what it was until I started reading the FSM trying to figure out why I couldn't bring the engine speed back to idle with the throttle lever anymore. So, here I am. I guess the only thing it can be is the governor gear inside the engine. I don't know why sitting would make that break, but I don't know what else it could be at this point. I put that spring on it to make it return to idle before it spun up the RPM's too high like it was trying to do.

Since nothing was moved, taken apart or adjusted I guess I just have to pull the engine apart to see what's up with that gear. I was really hoping I could find some other solution. There's a really high probability that I'll break off some bolts as one valve cover bolt already sheered off with minimal force. I'm pretty scared to try the engine case.

 

[bertsmobile1]

Fine but that does not preclude the govenor lever slipping on the govenor shaft then having some one notice the nut it loose & tighten it up at the wrong setting.
Read the govenor adjustment section a few times then recheck the engine.
The throttle lever sets the maximum that the throttle can open to so when you throttle down it should close down the throttle.

 

[BrownCoat]

Fine but that does not preclude the govenor lever slipping on the govenor shaft then having some one notice the nut it loose & tighten it up at the wrong setting.
Read the govenor adjustment section a few times then recheck the engine.
The throttle lever sets the maximum that the throttle can open to so when you throttle down it should close down the throttle.

I guess it could have slipped. No one has ever adjusted it, I know that for a fact. I'll check the adjustment on Monday. I guess I never considered slip since it hasn't ever moved in the 20 years we've had it. I'll make sure to check it.

Thanks, Bertsmobile. I appreciate your help.

 

[BrownCoat]

Still no luck with any of that. I ran it pretty hard for about 4 hours and it seemed to help it a little. Maybe the flyweights were/are stuck. Like I said, nothing was changed.

I guess I'll have to pull the engine down at some point to see. For now, I guess I'll govern it myself. I'm at a loss.

Thanks again.