01SeaRayBR
Cadet
- Joined
- Jun 5, 2011
- Messages
- 29
Hello everyone, long time reader, I am in need of some expertise. I have a 2007 mercruiser 5.0 mpi (serial #0w656595) with an alpha gen 2
(don't know the serial#) that is raw water cooled with the single drain system.
It overheats at idle while on the muffs and in the water. I have replaced the circulating pump on the front, replaced the thermostat, tested the thermostat, backflushed then entire system. I removed the manifolds and risers,cleaned them out, I just purchased the boat so I am unsure how old the manifolds are. I removed the outdrive and checked the hoses and checked to make sure the exhaust didn't have any restrictions. I bypassed the outdrive, power steering cooler, and fuel cooler and hooked the water hose directly the cooling system( the water distribution bulb at the bottom of the engine that has the drain valve), still overheats. Very slowly. It creeps up, gets in the 160s and 170s,lingers, fights the good fight, then eventually loses and overheats. My water hose has plenty of pressure, I even checked the ball check valves on the bottom of the engine to make sure they weren't stuck. I am out of ideas, this single drain system confuses the heck out of me. Please help.
Thank you,
Nic
(don't know the serial#) that is raw water cooled with the single drain system.
It overheats at idle while on the muffs and in the water. I have replaced the circulating pump on the front, replaced the thermostat, tested the thermostat, backflushed then entire system. I removed the manifolds and risers,cleaned them out, I just purchased the boat so I am unsure how old the manifolds are. I removed the outdrive and checked the hoses and checked to make sure the exhaust didn't have any restrictions. I bypassed the outdrive, power steering cooler, and fuel cooler and hooked the water hose directly the cooling system( the water distribution bulb at the bottom of the engine that has the drain valve), still overheats. Very slowly. It creeps up, gets in the 160s and 170s,lingers, fights the good fight, then eventually loses and overheats. My water hose has plenty of pressure, I even checked the ball check valves on the bottom of the engine to make sure they weren't stuck. I am out of ideas, this single drain system confuses the heck out of me. Please help.
Thank you,
Nic