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skiman53
07-16-2009, 05:39 PM
I've read the other posts about overheating. I bought the 225 Maristar new in '95 and have the LT-1 and love it. I've only had a couple overheating problems and solved them by replacing the impellar or back flushing the tranny oil cooler. However, a year ago, my impellar blew up and disintegrated in the case. I replaced it and didn't have problems. This summer, the boat will run for a while then peg out and over heat. I've replaced the top thermostate by the impellar housing and found chunks of rubber in that thermostate. I then flushed the oil cooler again. It will still run okay at 3,000-3,200 rpms, but if I get over 35 MPH or 3,600 rpms, it overheats immediately. I turn the engine off and can actually hear air being sucked through the hoses. I can't find or see any collapsed hoses.

I've never replaced the other thermostate and not sure where it's at. Am I missing anything? How can I back flush the engine to get the rest of the darn impellar pieces out of the block? The new thermostate on top of the block, by the impellar housing is NOT blocked and no rubber in it.

Thanks for any help.

Skiman53
1995 Maristar 225
812 hours and running hot

JLeuck64
07-16-2009, 08:15 PM
I gotta reach out to a fellow MC owner with an LT-1...

I wish I could give credit to the person who originally uploaded this schematic of the LT-1 cooling system but I don't know who actually did it. I saved a copy on my computer in case I ever needed to diagnose an over heating issue. Thankfully that has not happened to me yet (knock on wood!)

This schematic will show you the location of the second T-stat. Beyond that, if it were me I would start by taking a hard look at some of the smaller hoses for restrictions, pull em off and blow through them to make sure they are not plugged up. With a known history of scattering an old impellor I would not be shy about opening up as much of the cooling system as I felt comfortable doing in order to dig out those old pieces.
Good luck,
J

skiman53
07-17-2009, 06:08 PM
this diagram is invaluable. Thanks a bunch. I at least now have a map of where I'm going. Even if I have to pull the goofy impellar again, I can and probably should do exactly as you suggested. I want to do this once..and I've only pulled a few of the hoses on this monster. It's done me right over the years...so I can't complain about this little problem. Again, you've been a great help.....JLeuck64. You wouldn't be a Trekkie, would you??? If not, ignor my question, if you are, you know why I asked...lol....

JLeuck64
07-17-2009, 06:26 PM
You wouldn't be a Trekkie, would you??? If not, ignor my question, if you are, you know why I asked...lol....

I would say I am more of a Trekker, not a Trekkie...

(Trekkie's go to the conventions and dress up like their favorite characters... I just watch the old re-runs to death!)

skiman53
07-19-2009, 10:04 AM
ditto....I would be shocked if I haven't seen every episode of the original series and all the following, including ...well...all of them...lol....when I was in school, that was my escape from practice and classes....the old reruns...lol.....anyway, thanks for the help. I've printed the attachment and off to the lake to work on the Monster...will let you know what I find/discover/tear up......

skiman53

bigmac
07-19-2009, 11:05 AM
I wish I could give credit to the person who originally uploaded this schematic of the LT-1 cooling system but I don't know who actually did it. I saved a copy on my computer in case I ever needed to diagnose an over heating issue. Thankfully that has not happened to me yet (knock on wood!)

This schematic will show you the location of the second T-stat. Beyond that, if it were me I would start by taking a hard look at some of the smaller hoses for restrictions, pull em off and blow through them to make sure they are not plugged up.

J

On my MCX, the transmission cooler is AFTER the raw water pump. On the LT-1, is it BEFORE the RW pump, as shown in the diagram?

Craig
07-19-2009, 12:08 PM
On my MCX, the transmission cooler is AFTER the raw water pump. On the LT-1, is it BEFORE the RW pump, as shown in the diagram?

Yes, on my LT-1 the tranny cooler is the first thing raw water hits.

redlightning
07-22-2009, 07:18 PM
Great Diagram!
Thanks. I tried to get something like this from mastercraft and apparently it doesnt exist. I bought my 225vrs used and wanted to make sure the cooling system is all correct. I am stll having a heat issue but working thru it.