overheating 350 above 1800 rpm

[hybridgt]

I have a 1984 Sea Ray 245 with marine power 350 325hp and a alpha 1 gen 1 outdrive, now I'm new to boats, but have about 18 years experience in automotive so I know the main engine and mechanics of it, but I am having trouble with it overheating above 1800 rpm otherwise it runs fantastic (except with I forgot to turn the water hose on and ran it dry, will be replacing the impeller and housing tomorrow) but it had this problem before my screw up. I read that I should check the flaps in the risers to make sure they are free, is there anything else I should look for everything seems to check out otherwise, could it be the sea pump on engine and how would you check this? thanks

 

[Don S]

Re: overheating 350 above 1800 rpm

I read that I should check the flaps in the risers to make sure they are free,

Be careful what you read, those flappers keep water from sloshing back up into the exhaust. Has nothing to do with your overheat.
Fix the raw water pump impeller and housing/s if needed and see what happens.
The impellers are an every other year replacement item. They don't last forever.