You got me. I've never seen this. Is it a mechanical control of some kind, or are there just electrical wires going to this?

 

It's a mechanical control, looks almost exactly the like the throttle control. I need to trace the cable back, I'm almost sure it's the choke.

 

most definitely the choke. Now I realize the carbs not right, choke has to be on in order for it to run. I'm guessing the float needle is sticking. Going to tear it down, soak, re-install and see what I get....

 

Having to keep the choke on indicates it is running too lean. That is the opposite of a stuck needle valve where you would have too much gas flooding the engine. Could you have an vacuum leak perhaps? Try spraying carburetor cleaner around the carb external body/intake manifold when the engine is running. Any change in engine speed indicates an air leak.

 

either way it needs to be cleaned..

 

carb is cleaned and it runs great, it does idle a bit high even with the idle adjust screw completely backed out though. Is that normal for these engines?