Honda hs520a governor arm vibration

Hello-

Honda hs520a snowblower with a gc160 engine. I had a surging problem so I recently replaced the carburetor. Also adjusted the valve lash. Engine seems to be running well. Next problem is governor arm seems to vibrate excessively near the throttle plate. I am not sure if it did this before because this is the first time I have had the top cover removed. Seems like a weird engine harmonic is causing the vibration because if I adjust the engine speed there are different speeds at which the vibration is better/worse. Also the speed control lever is very near the end of its adjustment at 3600 RPM.

I am thinking the governor spring or throttle return spring (the one between the governor arm and throttle plate) are stretched. Also seems like a little groove is worn in the end of the governor arm from the governor rod from wear or vibration. Looking for your expert ideas before I start throwing more parts at it.

 

There should be a thin spring over the throttle linkage that holds the linkage tight in the hole on the governor arm to keep it from vibrating much. Is it there or missing? I'm thinking that is the one you're talking about in your post, and if so, it should not be loose. You might have to shorten it a little bit.

 

Yes, I think Honda calls that spring the throttle return spring, but it is captured along the linkage between the governor and throttle. It does seem stretched and not much tension. I will try to adjust or replace it. Thanks for your help.