03 SD Engine Temp Range 350 mag mpi

[SeaRay240]

Hey Guys how is it going today.. About six months ago I purchased a 03 24sd 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 for more than 2-3 minutes at that temp.

It has 85 hrs now did the 100 hr service changed the impeller. Have not got it back out on the water yet but when i hook up the hose it wont get hotter than 134 Degrees. Does that seem to low or is that a normal range between 130-160 degrees.

Thanks guys, Mike

 

[Dave S]

Right around 160 is about average. Were they able to find all the pieces of the broken impeller and remove them? Since it is running cool I would drop it in the water and go for a spin and see what the temperature registers.

 

[SeaRay240]

We got some of the broken pieces. I don't know about all of them. All the blades on the impeller were broke. I'm not sure if it has ever been changed before because the boat didn't have much use. I will be taking it out on Friday if it runs that cool could it be that the thermostat is stuck open?

 

[Dave S]

We got some of the broken pieces. I don't know about all of them. All the blades on the impeller were broke. I'm not sure if it has ever been changed before because the boat didn't have much use. I will be taking it out on Friday if it runs that cool could it be that the thermostat is stuck open?

That's a possibility but if it came up to the 134 degrees quickly, then I wouldn't think the thermostat was stuck open.

 

[Firerooster]

At idle on the water or with a hose u may only see 135 or so. Put it in the water. Once it warms up a little, open her up, bet u see 150-170 easy. Then hit the cove and idle on in. By the time u get to the back of the cove u will see 135-140 again. All sounds good man, enjoy it

 

[SeaRay240]

Ok guys thanks for the responses. Ill hopefully be out on Friday I will see how it goes.

 

[highslice]

Actually, my 240 with the 350 Mag always ran between 165 and 180. It always ran hotter at idle, about 175 to 180. When I was at cruising speed, with the water really running, it would run closer to 165.

Check the thermostat if you can't get it up to temperature, maybe part of the impeller is keeping it open. But you want the engine running in it's optimal temperature range.

 

[skolbe]

When I idle and/or am on plane the temperature is always about the same. From the upper 150's to the upper 160's depending on water and air temp - when the thermostat is stuck open the boat runs cold. Probably 120's/130's - I had one stick - and quickly replaced it - if you are running cold you will have carbon build up in your motor. A guy on our dock thought it would be wise to run without thermostats. After 2 years - he sprayed mercury's Quickleen into his carburetors - sheets of black crud started coming out of the exhaust. It layered the marina.

 

[SeaRay240]

Yea like I said it always ran from 152-160 every time I have taken it out. Then I had the problem with the impeller. After we replaced it we started it up and it was in the 156-160 range. The last two times I have started it up It doesn't go up more than 134 even after 10-12 minutes letting it run. I'll try it out on the water Friday and if its still really low I will guess its the thermostat and see what I can do. Thanks for all the replies everyone

 

[SeaRay240]

Ok guys so I had a chance to take it out today. Assuming the smart craft is fairly accurate I got to see what temps the boat ran in the water.

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 140 after a few minutes and stay there.

Seems like the range of temps should be a bit closer? Maybe its stuck partially open. Anyhow mine as well change the thermostat I'm sure it hasn't been done.

Thanks for any more input you all have appreciate it guys