Mercury 25HP, 1985 electric start running fine except for a bit rough and occasional miss at idle, taken to dealer for routine service. Dealer advised electronic module down as reason for rough idle, also replaced impellor. Compression on both cylinders reported as good at 130. Boat used at slow speeds for two days then stopped pumping water and got hot (steam at tell tale) but did not seize. Took back to dealer who now says that gasket on side plate failed and exhaust gas pressure prevented water from flowing around head as reason for overheat. Has now planed side plate so that it seats, replaced head gasket and says now OK but I should now trade up to new motor. I don't know much about motors, does this all sound legitimate. If not, any ideas on cause of overheat so soon after service.<br /><br />Thanks....Optimistic
