1980 Mercruiser overheating (Temp gauge pegs out and engine stalls, manifolds over 200 F) when run above 800 RPM. Century Resorter straight inboard. 350 Small V-8. Cooling water circulates, but erratically. Fresh water use only. The following actions have been taken without solving the problem:
Replaced thermostat (twice!)
Replaced water pump impellor
Checked all water lines and water intake for obstructions or restrictions
Replaced recirculation pump (After seeing YouTube video on this topic from the guy in Florida)
Removed and reground both cylinder heads.
While running thermostat housing alternates from hot to cold indicating normal open/closing, but the logs do not cool once they've gotten good and hot. The mechanic has given up! Says there's nothing more he can think of to do or check.
Any insights or suggestions?
Replaced thermostat (twice!)
Replaced water pump impellor
Checked all water lines and water intake for obstructions or restrictions
Replaced recirculation pump (After seeing YouTube video on this topic from the guy in Florida)
Removed and reground both cylinder heads.
While running thermostat housing alternates from hot to cold indicating normal open/closing, but the logs do not cool once they've gotten good and hot. The mechanic has given up! Says there's nothing more he can think of to do or check.
Any insights or suggestions?