That is a lot of weight!

It sounds like it may be trying to backfire when turning over have you went through the carb to make sure all is good.

Top end or full rebuild, engine come out, it sounds like linkage adjustments are needed, which would be typical if engine came out.

My uncle hit a guy across his head with MAg lite 4 cell flash light. He said he swung as hard as he could . The guy just rolled over and did not move. It splt the guys head like a mus mellon. Blood pouring over his face. My uncle said he figured he :"Kilt him" ( Killed him ..flatlander speech) My uncle said he was busy trying to make sure his female deputy sheriff partner could breathe. The guy had her down coking her. My uncle said it was faster to hit the guy than shoot him and risk hitting his partner. He said while he was reviving his partner the guy got up and ran, The mag lite is aircraft grade aluminum.