O.T Briggs Stratton Quantam engine

We have a couple of those--both 5 HP vertical shaft and both pretty much worn out, smoking and needing rings if not junking. A couple of maybe things--make sure the linkage cable hasn't slipped past the normal clamping point so you're not getting the full "stroke" of the throttle adjustment. 2nd, I'm told by a local fellow who does alot of mower repairs, that those engines have a plastic governor gear that's easily broken or maybe one tooth is cracked/broken. Could be that happened when they were beating on the crank. As a last resort, I adjusted the idle screw on ours when the governor wasn't working properly. This provides a higher throttle setting but doesn't help with the "droop factor" in thick grass from not having a governor.