Kohler K/M governed idle and sensitivity

[RED-Z06 2,245]

My M12S runs great except at low throttle input, at say 1/4 throttle i dont get governor compensation...even at near 1/2 throttle, i get little response under a load.

 

I did the static governor reset to be sure, and it hits 3600-3650 at full throttle.  My throttle only responds from about 3/4 of the lever position on up to full, below 3/4 its just jamming the long governor spring and forcing it to hard idle against the stop screw.

 

What am i missing here...

[peter lena 8,720]

@RED-Z06 notice a lot of related rust in the area? did you ever lubricate the both ends of the governor shaft swing points ?  in the engine ?  had a similar issue years ago , once i regularly started to lubricate the governor swing shaft , like at every start , the rust started running out and the governor started working with total ease . would also check over entire linkage function , like does it move without effort , penetrating oil at every swing point . just some ideas , pete

[RED-Z06 2,245]

5 minutes ago, peter lena said:

@RED-Z06 notice a lot of related rust in the area? did you ever lubricate the both ends of the governor shaft swing points ?  in the engine ?  had a similar issue years ago , once i regularly started to lubricate the governor swing shaft , like at every start , the rust started running out and the governor started working with total ease . would also check over entire linkage function , like does it move without effort , penetrating oil at every swing point . just some ideas , pete

Im not seeing any noticeable binding or stiffness, just a lack of spring tension at idle..the governor itself seems very sluggish and slow to respond 

[RED-Z06 2,245]

Maybe my governor gear is broken inside...lost a weight, it just seems to work fine at or above half throttle.

[RED-Z06 2,245]

This is idle, where it just starts to pull on the governor.

 

Half, and full throttle 

[pfrederi 17,866]

I know manual says #6 hole but to increase sensitivity have you tried moving the spring up . My M16 is happy in #5

[pfrederi 17,866]

There is no good picture /explanation in the manual about remote throttle...  However on my M16 the throttle pivot the spring is in the second hole from the end (not sure it correct but it works) yours is much closer to the pivot point

[pfrederi 17,866]

One ore thing from your picture it looks like you are missing the throttle stop ( a plate on eh inside of the instrument panel that keeps the throttle from going all the way down to the end of the slot.

[pfrederi 17,866]

[RED-Z06 2,245]

17 minutes ago, pfrederi said:

There is no good picture /explanation in the manual about remote throttle...  However on my M16 the throttle pivot the spring is in the second hole from the end (not sure it correct but it works) yours is much closer to the pivot point

That should give mine more rotation with less reaction though right?  Ive tried to move things for more lever movement and less linkage movement, i went up to thr 4th hole and adjusted the speed back up but it felt too touchy.

[Rusty Tinsnips 477]

27 minutes ago, RED-Z06 said:

This is idle, where it just starts to pull on the governor.

My 72 Raider 14 throttle is exactly like yours. I have not been able to figure out why I only have 1" of throttle response.

[RED-Z06 2,245]

The more i ponder it, i think my governor gear is broken, less resistance on the flyweights means it comes out too soon and the spring has to be kept semi loose to keep peak rpms in check.

[Rusty Tinsnips 477]

My governor operation seems to work fine, I just don't have any throttle lever range.

[pfrederi 17,866]

This M16 is on a hydro so I sort of run near full throttle all the time but these linkage hookups seems to work OK

 

Governors always seem like a bit of black magic to me.

 

 

 

[RED-Z06 2,245]

Here is video of it vs my K241S, the m12 was as 3/4 then full throttle, it never really hits full throttle when compensating like the K does and there is a pronounced jumping in it.  

 

 

[RED-Z06 2,245]

Confirmed governor failure, i pulled the camgear cover and took a peak...1 weight intact and one missing its pin and weight.

[gwest_ca-(File Mod) 11,090]

They came out with different cables but the procedure should be the same for the original cables.

Sounds like your governor is operating correctly. I think if you reposition the cable casing where they are clamped it will work.

 

You realize the governor tries to reduce rpm? It is the throttle cable and spring that increase rpm.

The faster the rpm the more force the governor develops to reduce the rpm.

That force equals the governor spring force to give you the rpm desired.

[RED-Z06 2,245]

2 hours ago, gwest_ca said:

They came out with different cables but the procedure should be the same for the original cables.

Sounds like your governor is operating correctly. I think if you reposition the cable casing where they are clamped it will work.

 

You realize the governor tries to reduce rpm? It is the throttle cable and spring that increase rpm.

The faster the rpm the more force the governor develops to reduce the rpm.

That force equals the governor spring force to give you the rpm desired.

Yes, the flyweights sling out and force idle, the spring pulls the throttle open and pushes the weights in...engine speed goes up and acts against the weights pushing them out harder, eventually finding equilibrium at the governed speed.  As load increases, engine speed drops and the spring starts to win...engine speed is increased by the opening throttle...which goes back into equilibrium.

 

In the post above the gear is broken, one of the 2 weights has slung off, ive got a new gear coming then ill be able to make the correct adjustments and have proper governor function.  Fun part is it has to be nearly bare blocked to do it...cam and crank out..etc

[kpinnc 12,382]

I suggest adding a light spring between the governor arm and throttle tab on the carb. This eliminates slop in the governor linkage, and greatly enhances throttle response.

 

Light springs like this are available at most any hardware store, and are small enough to cut and shape however you want. The holes for the spring are likely already in both components, and I am always confused why they don't get installed at the factory.

 

All this after you replace the gear of course.

 

 

Edited December 28, 2021 by kpinnc