I have1975 merc. 850 85 hp (2 stroke 4 cly) It starts with no problem runs fine for 3-4 min. them just shutdown, and wont'restart until it cool down then restarts and may run for 30 min with no problem seem to be an intermidiate problem with no spark firing when engine get hot this is not an impeller problem could this maybe an electrical thing like the switch box (this has thunberbold ignition. so I don't think it has a coil or does it? Does not run rough <br />or misfire before shutdown just stop like the key was turn off.. ths for any help!! nriver
