Friend of mine had a cracked block after swallowing too much sand in engine. Swaped the engine with the same year same engine model, complete drop in unit. New impeller in sea water pump, new pump on engine, flushed all hose and drive from outside toward inside and inside towards outside. even tried without thermosthat, temp was the same except it cooled off faster when slowing down. Checked timing, checked water temp with a thermometer right in the outlet on the engine... run 175 at idle 183-85 on plane, then you hear the buzzer... roughly 10 degre more than port engine.
WHAT ARE YOUR TEMP ON THESE ENGINE ? I can't find the problem after like 12-15 hours on it!

What Are Your Temp On These Engine ?

depends on what stats you are running, I prefer 140s

My 502MPI 's run a 160 stat

I would use a laser temp gun while runing to confirm temps and where they are at, that should help narrow down your problem


and make sure you gages/ alarm senders are accurate

alarms should not be going off at 185

what temp they should be buzzing at then?

about 210