Mercrusier 5.0 Mpi Overheats At Idle

[MFSMH]

What to next? The starboard engine starts fine and is at 89deg. after 5 min. or so it shoots to 150deg. and rises 5deg. every 2 to 5 seconds till i shut it down around 175deg.(way to hot). I checked the thermostat and it is fine, cleaned the risers and reinstalled them. I touch the water pump feels cool. I am stumped and getting frustrated. Why would the temp jump up like that? Is it the sensor? The bravo 3s have been cleaned of all the barnicles and is totally clean,also when i give it some fuel the temp drops then back at idle it rises. Any suggestions would be very useful at this point.
Thanx

 

[MFSMH]

Re: Mercrusier 5.0 Mpi Overheats At Idle

Somebody anybody? Somebody out there has had some sort of issue like this out there. I can't be the only one. I'm going to look further into the sea pump impeller, but running out of steps to take. The gremlins have sabotaged my engine

 

[Don S]

Re: Mercrusier 5.0 Mpi Overheats At Idle

175? is normal, and where it should be running.

 

[Bondo]

Re: Mercrusier 5.0 Mpi Overheats At Idle

I'm going to look further into the sea pump impeller,

Ayuh,.... That's where you should have Started...

 

[MFSMH]

Re: Mercrusier 5.0 Mpi Overheats At Idle

Thanks for the input. Going to get an impeller kit and install it. Then put the sensor from the other engine in see how everything works out. Will reply with the results. Thanx again