View Full Version : ***Engine Over Heating***

07-05-2010, 08:58 PM
06' X-2 with MCX engine

Boat has been running fine. After making a 30 min trip up the lake to meet up with some friends to surf we slow down and fill ballast. Rider jumps in and we take off about the time I get up to speed perfect pass acts funny and I look and see the engine temp is starting to rise.

Just changed impeller at start of the year, but we go ahead and pull it out just in case and it is it good shape, but we go ahead and put the brand new spare in that I have.

Start engine and once I rev it up a little the temp starts to rise over 160 again.

So then we dig out a new thromostat spare my buddy has and we change it and still the same result as once I start gettng the engine up to the 2k and up rpm range engine starts climbing over 160.

Tow boat back to dock and we check the Tranny cooler for debris and nothing is blocking it. we go ahead and still take garden hose and flush it out.

We take ever hose off where the thermostat is and run water through them as well.

We have checked every hose and blew them all down / backflush with water and changed impeller and thermostat. we have checked and the water pump is pumping water.

What am I over looking??? What could it be?

W have also taken the new thermostat out that we put in and along with the one we took out and checked them and they are working fine too.

Please help.. Any Ideas?

07-05-2010, 11:12 PM
Is this an LT-1 motor?

07-05-2010, 11:32 PM
have you checked to see if it is actually getting hot and don't have a possible bad sensor? I'm assuming you did, and if so, you might have a restriction some where.

07-05-2010, 11:35 PM

A few years ago I had a similar problem. The mechanic checked almost everything. The problem ended up being a brand new impeller that spun freely on its metal shaft. Upon a quick visual inspection the impeller was perfect. When we tested with a fake-a-lake we could not get the engine to overheat because the water pressure from the hose forced the impeller to turn. Out on the river was different and the boat kept overheating. New impeller and no more overheating. Good luck.


07-06-2010, 06:10 AM
not sure on the sensor... but odd that it sits at 160 until it is revved upto higher rpm's then falls back down when back to idle.

impeller should be fine I have been working on it while in the lake and is pumping fine..

any other ideas? calling dealer today...

07-06-2010, 12:20 PM

07-06-2010, 12:24 PM
You sure the stat is opening all the way?

07-06-2010, 01:03 PM
You sure the stat is opening all the way?

yeah took the new one back out and put it and the one I took out in a pan and brought water to almost a boil and they opened right up