overheating problem 5.7 Mercruiser

[glmtrophy2352]

Want to thank those who replied to my mayday on 4/4/2008 about my overheating 5.7 in my 92 Trophy. I did as you suggested and got a Temp. gun and checked temps on block,heads,exhaust manifolds and intake. checked water flow into engine and engine water pump. Culprit was a malfuncting thermostat(brand new mercr. part)gave it the hot water test and the 140 degree thermostat opened at 175, so it got replaced and all is fine now.I will be watching the forums in the future , maybe I'll be able to assist someone with their problem. this is much better than trying to pick the brain of someone at a boat dealership!!