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Mercruiser overheating when trimmed up.

R

rockey_standish

New member
i have a 2014 Crownline Eclipse 25', w/a Mercruiser 320hp. There's a specific set of circumstances that are triggering the overheat alarm. When im underway, full throttle, and i trim the engine up even in the slightest bit, the squealing alarm is triggered. The boat is in pretty mint concdition so all intakes are clear and hoses are in good shape. I've had it in for service and they've been unable to figure it out- so far they have replaced the thermostat, temp sender, water pressure sensor, and exhaust check valves. problem still happening. they're stumped- any ideas?
thanks.
 
After you confirm the water tube in the transom assembly is open/clear and no air is getting in the cooling water stream...(Clear hose will show it) Then you have to look at the x dimension, it may be cut too high.
 
the boat is a 2014. i purchased it from a dealer this winter. i have to assume if the drive were at an imporper level, it would have been an issue prior to now? or could something have changed?
 
FWIW...... operating a boat more than occasionally for few seconds to verify proper engine tune is not a recommended operating condition... Continuous, i.e. cruise operation, should be limited to 80% of the max rpm you get at wide open throttle. But hey, it's your repair budget!!!!
 
Your drive hasn't been mentioned. Assuming Bravo? I thought Bravos utilized through hull water intakes. Wouldn't this negate the x dimension theory?
 
Just so I understand, the Bravo does not have an impeller in the drive. The pump is engine mounted but still draws water from the drive at a similar location as the Alpha?
 
Mark S. said:
Just so I understand, the Bravo does not have an impeller in the drive. The pump is engine mounted but still draws water from the drive at a similar location as the Alpha?
Click to expand...

Most of what you said is true.

Bravo = NO OUTDRIVE IMPELLER

Bravo or any engine with an engine mounted water impeller can pull from drive OR from hull. Depends on boat type.

In this case because he references issues with drive UP we assume the engine mounted impeller is pulling thru the drive.

As referenced in POST 2,
The main issue with this is Merc's method of the juncture of the drive to transom hose and the transom to impeller hose.
It uses a "pinch" style connection in the transom assembly and this area of the transom corrodes very badly and compresses the connection point of the two hoses and restricts water flow sometimes by as much as 99%.

Although we do not know this to be the issue for this post yet.
 
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