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Overheating

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pmr

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I have a 28'-0" Searay

I have a 28'-0" Searay Sundnacer with twin small block v-8 mercruiser engines. The right engine is overheating. So far the impellor has been replaced along with the circulating pump. The engine gets warm during idle but will not over heat. When both engines are running and the rpms are increased to plane the boat off the temperature steadily rises and the engine overheats. If you run the right engine only at full throttle the engine does not over heat but the boal will not plane off either. Weird! Any ideas?
 
"More info needed

year
eng

"More info needed

year
engine model
outdrive alpha or bravo
FWC or RWC
if FWC, how many heat exchangers
used in lake or saltwater"
 
Who did the impeller and why?

Who did the impeller and why?

Also what comes in must go out.....Pull thermostat and see if problem goes away.

If not answer guys questions!!!!!!!!

Details Details Details
 
"i have similar problems with

"i have similar problems with my twin 454 mercs, at idle temp is around 160, as soon as i get on plane both engine temp gauges start rising and before they reach 200 i bring boat back down to idle speed and then the temp gauges come back down as well. these engines are fresh, bravo drives are oringinal 1989's, 160degree thermostats, new oil coolers, what would you do next without calling the mobile mechanic? Dave G"
 
"D;
If they use thru-hull pic

"D;
If they use thru-hull pickups, that's where I would start.
The pickups or sea strainers may have a crud buildup.

Patrick;
Your stbd pump may be picking up air causing the overheat.
You should insert a length of clear plastic hose in the inlet line to the heat exchanger or stat housing, and look for bubbles as it runs.
If you see any air, your drive needs to come off and the pump rebuilt to eliminate air pickup.

Rod"
 
like Guy said need more info b

like Guy said need more info but you should have alpha gen2 outdrives and should be raw water cooled I have the same boat 280 Sea Ray. replace your thermostat and go from there..
 
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