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Closed cooling system

rcaponeg

New member
I just installed a closed cool

I just installed a closed cooling system on my brand new 5.0 MPI Mercruiser. After the initial fill and test I noticed the starboard exhaust elbow running hot. I took the boat for a test run and at high rpm the elbow runs cool. The engine does not overheat. I think that there is not enough water flow at idle to cool both exhaust elbows. Could I have a pump problem even though this is a brand new engine? The dealer told me when I picked up the boat that they changed the water pump housing because it was cracked.
 
"Robert, I was informed by a d

"Robert, I was informed by a dealer that for the V8 motors they used a thru hull raw water pickup and an engine mounted pump to supply water for the closed cooling system. It seemed that the outdrive mounted impeller pumped enough water for raw water cooling, but not for closed cooling."
 
"I have a closed cooling syste

"I have a closed cooling system in my 5.7L. It's an aftermarket kit installed by yours truly. I haven't had any problems with not being able to cool the engine or the risers with just the outdrive mounted impeller. I have yet to run it in notably warm water then the Gulf of Maine, and I'm standing by to provide additional flow should it be necessary as the Virgnia sunshine warms the water thorough the summer.
Something strikes me as percular:
"The dealer told me when I picked up the boat that they changed the water pump housing because it was cracked."
- How did the dealer know this?
- Why did they have it apart in the first place?
- Why was it cracked... it's new right?
You might want to get the rest of the story there.
I'd bet you got something less than quality work with regards to the new pump housing."
 
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