I have a 70’s model Johnson 20hp on the flat bottom. Whenever I know it’s gonna be sitting a while I run the gas out of the carb,same with the big boat. But I also premix. I never have a problem. I also clean the carb every other year. Can’t beat a 2 stroke. Diesel or gas haha. I’ve always ran Johnson engines. Prob because pawpaw was a Johnson evinrude mechanic so I’m kind of bias. But never had a problem with them. Had a 135hp and drove it all the way back to the ramp with a broke in half crankshaft!!!!! No kidding