Logo

Running Hot

carlnap

Contributing Member
"I just replaced my thermostat

"I just replaced my thermostate because it was flucuating and running on the cold side (140). Put a new thermostate in that is rated to read 160. At idle it's reading 160, until I reach cruising speed it reads 180. how can I check if there is a blockage of water from the lower unit to the thermostate. I have a 2003 5.0 mercruiser mpi bravo 3."
 
Bravo 3 gets its cooling water

Bravo 3 gets its cooling water from a seawater pump located on the LOWER starboard side of the engine. Has the pump impeller ever been changed? Look and FEEL the hoses connected to it along their entire lengths to see if one is pinched or soft and failing. The water inlet hose could be weak and collapsing under high RPM.
 
Back
Top