Elevated temperatures in 2004 196

[markn]

Boat has always operated in the 155-165 degree range. Recently noticed after several slalom passes while at idle, temps increase to 180 degrees. Once under load again, it declines back to around 165 degrees (slowly). I have changed the impeller (which looked good, but replaced anyway), checked the strainer and o-ring, replaced the thermostat and checked the transmission cooler inlet/outlet. The only thing I have not done is change the belt. Any ideas or suggestions on what else to check before calling in a mechanic? Thanks for the help and insight. MWN

[dbutcher]

The symptoms are those of sucking air somewhere (anywhere) on the supply side of the impeller, but it sounds like you have checked for that. Could there be a partial restriction of the water intake that is overcome at higher speed? It really doesn't sound like a bad temperature guage or sending unit, but they are remote possibilities. I assume there are no water leaks anywhere in the cooling system. A hose clamp in the wrong position (such as on the transmission cooler) can cause the system to suck air. Good luck.

[FLeboeuf]

It is normal for the temperature to increase a little more than normal after a slalom pass when you stop and put the boat to neutral to shorten the rope or something. The boat is under load, the temperature increases, but water flows more in the block Somthe temp stays normal, but the moment you stop after a pass, the engine is still at "under load" temperature for a little time and the waterflow decreases somthe temp increases a little. But after a few minutes like 1 or 2 max usually the temperature comes back to normal and even lower. And if you dont let the time for the temperature to get back to normal and go for another pass, the temperature goes back down because of the increased waterflow.

Thats what my Nautique dealer mechanic says. So it might be normal unless the temp stays at 180 all the time at idle. Water temperature affects this too.

[markn]

Thanks to all for the responses. Guess I will just monitor closely. MWN

[FLeboeuf]

Youre welcome. I was also thinking maybe the circulating pump could be starting to wear down. It could be working well at higher speed since it spins faster. At idle, if there is something wrong in the pump, it might not spin fast enough to overcome whatever restriction there is in there. I would worry only if the temp is at 180 all the time at idle. And check you boat manual, for my boat overheat occurs at 200, I know older engine overheat occurs at 220 so if its the case 180 shoulnt damage your engine but it could be not normal

[markn]

OK. I officially feel like an idiot. Still hot and getting hotter after checking all the above, Even put teflon tape on the strainer treads thinking it was sucking air. While checking, touched the belt and it was extremely hot. Changed the belt and temps never above 158 degrees now. Oh well, have a new impeller and thermostat, and now new belt for the season.

 

Thanks again for the help and insight.