Overheating 87 18 classic

[chappy]

Hello All,
Just looking for a little guidance. I own an 87 classic with a 350 merc magnum. While cruising at 2400 rpm, engine temp is fine. When I push it to 2800-3000 rpm, the temp slowly climbs over 210 and the high temp sensor goes off, I then drop down to 1200, and raise the hatch and let the engine cool for 5 minutes. The boat lives on a fresh water lake in Pennsylvania. The boat used to live on the Long Island Sound and was moored in the salt water for 4 months at a time for many years. I've replaced the impeller, cleaned out the exhaust risers/elbows, which were really blocked. My question is, do I pull the manifolds? Does the salt water damage the water circulating pump? Or should I just pull the manifolds and clean them? I'm tempted to replace the manifolds, risers/elbows, and the circulating pump. I'm just looking to save a little money so I can run WOT without worrying about the temp problem.
Thank's for any help,
Chappy
(a boat is a hole in the water you throw
money into only if you don't use it!)

[gcarter]

How about the power steering and/ or the engine oil coolers. These are usually on the water inlet hose and can really get nasty.

George

[MOP]

How about the power steering and/ or the engine oil coolers. These are usually on the water inlet hose and can really get nasty.

George

George is heads up on the oil cooler stuff gets sucked up and it gets plugged slowing the flow, the circ pump can replaced with a cross over if you are raw water cooled, not so with closed cooling. The cross over is cheaper than a new pump and gives you one less thing to worry about and a tiny tad of power not having to drive the pump. Check them out on Stainless Marine site.

Phil

[clayman]

Chappy, you may want ot read the recent thread I started about my 1986 18' classic overheating as well. They gave me alot of tips on things to check. And, I am happy to say it was the $4 balls in the thermostat housing that did the trick on my problem.
Jim