Throttle Links Broke My Shaft!

I've got the 861 running right - idling at 475 and no longer bogging down above 1800. Turns out all she needed was a clean fuel line and new gaskets. While I had the carb apart I replaced anything worn or broken, most notably the throttle shaft.

The connection between the bronze shaft and the steel arm that connects to the governor linkage was so loose it was ready to rip right off. I had previously epoxied that spot as a temporary fix. The problem it seems to me is that the low idle adjustment screw is what bottoms out all those linkages at low idle. I know to be delicate with the old gal, but in my humble opinion this little bronze swaging ain't skookum for that 200lb gorilla in the driver's seat.

For the high end RPM I know to set the screw on the linkage against the bracket coming off the manifold, but there is no such bracket for low idle setting. Perhaps there should be. I believe I have all the adjustments to the governor and throttle linkages done correctly per the directions in the owners manual (and the I&T shop manual). I've also freed up and lubricated the spider washer keeping tension on the hand throttle.

Have I adjusted the linkages incorrectly? Is there something I'm overlooking? Are there alternatives? Opinions welcome.


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Welcome to the forum!
Your movement of the hand lever moves the governor, the governor
then moves that shaft, so you're not breaking it by moving the handle.
The shaft is replaceable if it is broken. I have also brazed them back together.
Just make sure the seal area is in good shape. If not, replace it.
 
I have to say, your pictures are some of the clearest ones I've seen posted here.

As Royse said, there's not a lot of torque on the throttle shaft.
 
(quoted from post at 20:22:51 09/30/19) Welcome to the forum!
Your movement of the hand lever moves the governor, the governor
then moves that shaft, so you're not breaking it by moving the handle.
The shaft is replaceable if it is broken. I have also brazed them back together.
Just make sure the seal area is in good shape. If not, replace it.

Thank you for the welcome and the confirmation. So this is a common issue. I'd rather not have to replace the shaft ever again if there's anything I can do to help it.

It seems there is quite a bit of force on the throttle shaft. The hand throttle directly pushes the governor arm which pulls on the throttle shaft. The idle adjustment screw is the only thing that bottoms out out those links. Because the hand throttle has a radius of 6 inches or so, and the throttle shaft link has a radius of about 1 inch, that's 6x mechanical advantage. That's my gorilla arm times 6 acting on the shaft. No wonder it breakes.
 

Thank you, Mark. They're base model Samsung Android smartphone pictures. I'm sure I'll be posting more - I have lots of questions. I'm very thankful this forum is so active.
 
(quoted from post at 10:01:27 10/04/19)
Thank you, Mark. They're base model Samsung Android smartphone pictures. I'm sure I'll be posting more - I have lots of questions. I'm very thankful this forum is so active.
ractor 60 years old! Nothing lasts forever. If replacement lasts another 60 years, I bet all will be good for you. :)
 
(quoted from post at 07:13:49 10/04/19)
(quoted from post at 10:01:27 10/04/19)
Thank you, Mark. They're base model Samsung Android smartphone pictures. I'm sure I'll be posting more - I have lots of questions. I'm very thankful this forum is so active.
ractor 60 years old! Nothing lasts forever. If replacement lasts another 60 years, I bet all will be good for you. :)

That's true. I'll be lucky if I'm able to drive a tractor 60 years from now.
 

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