I have Mariner 25 around 10 years old, it is hard to start cranks good but kicks back,usally have to hand start, after it is started it runs good and restarts fine
i had a 55 chrysler that was doing the same thing. mine turned out to be flywheel needed retorqing. when it was cold it was a littele loose but when it warmed up it tightened up. it worked on mine hope it workes on yours.