350 mag mpi Temp range

[SeaRay240]

Hey Guys how is it going today.. About six months ago I purchased a 03 24 sea ray sd 350 mag mpi. Had 68 hrs on it. Took it out a few times everything ran really great. Always ran between 152-158 degrees. The impeller went bad (it looked destroyed but it probably has never been changed before) when i went out and it started getting hot immediately. Cut it off as soon as it got to 205 and didn't let it run around those high temps for more than 1-2 minutes.

So the first time taking it out since getting it fixed. Assuming the smart craft is fairly accurate I got to see what temps the boat ran in the water. On the hose couldn't get it past mid 130's seems low.

Starting out it warmed up kind of slow I think staying around 128-130 at idle speed. Slow speed got around 140-145.

Took it out in the ocean a good 30minutes of running around 25mph temps were at a consistent 165-170. Did not go over 170. I noticed though as soon as I would slow down temps immediately dropped to 150 almost instantly and when I would go back to idle speed it would drop to around the 140's after a few minutes and stay there.

Seems like the range of temps should be a bit closer but idk? Maybe the thermostat its stuck partially open or could be normal now that I have a proper working impeller.

Thanks everyone, Mike

 

[bomar76]

Re: 350 mag mpi Temp range

Did you get all the old pieces of impeller out of the power steering and oil cooler(s)?

 

[SeaRay240]

Re: 350 mag mpi Temp range

Yes I believe so. The guy who worked on the boat does all the us custom boats and knows his stuff. We pulled out some pieces. He also did the 100hr service.

I believe 170 is a normal temp for this engine but is it normal for about a 20-25 degree difference between slow/idle speed and cruising speed degree or should it stay more steady? When I was running it opened up a bit in the ocean then slowed down to slow speed it dropped 20 degrees almost instantly