Re: johnson 85hp v4 1979
Only if it was so hot that the flywheel melted into the engine. I dont think you would be keen to go boating if it was that temperature outside.
Pull your plugs out and see if it makes any difference. It should be pretty easy by hand then too. If its not easy you have an engine problem.
I suspect you have a worn starter, solenoid, or cables.
Check its not the engine binding up first