I have owned 2 gms 76's and they were both great runners but required a lot of needle fiddling for the first 2 or 3 tanks. the 76 likes to be run on the rich side and a tuned for max rpm the engine will run lean when the tank drops below 1/2 full. richen it up and by the way I still have a brand new muffler for a gms 76 I would sell reasonable if anyone needs one