RE: MVVS 58 HIGH IDLE
If you can cut the engine by closing the throttle further, than it is not a mechanical problem. I once had a problem with my MVVS 58 where the screw holding the throttle butterfly in place, came loose. You need to close the throttle with this screw loose, and ensure that the butterfly seats properly against the walls of the carb walls. This can sometimes take some fiddling. When tight, look through it, and see that it closes evenly all the way around the butterfly.
Another problem I have had is the small mesh filter gets blocked in the carb. You think is is clean, until you hold it up to the light. After a couple of years of storage, you may find that the residual oil has dried in this filter, partially blocking it. I had all sorts of idling problems when this happened. A lean idle raises the idle speed, and the throttle linkage only needs a fraction more movement to cut the motor.
Good Luck