HOT or NOT?

[Searenity]

Hey guys, hope everyone is haveing a good season.Since I got my new boat every weekend has been sunny(hope i didnt jinx myself) Ok I have a 1999 merc 150 oil injected carb motor on a 21 ft proline walk around. I basically have 2 questions when I am idling around the temp goes up to 220 whick is the far end of the guage, this worries me,Yet No alarms sound..then when I can get her moving along at a better speed the guage goes down.Is this normal? Next which freaking oil should I use? I always stay with Merc oil, but there is a plus version and would this be better for my motor?<br />Well, thats about it for now, thanks

 

[KCLOST]

Re: HOT or NOT?

I'd service the water pump (replace impeller) and t-stats... That sounds a little high at idling/cruising speed. Do you have a good water stream at 220F?<br /><br />180-190F is more normal....

 

[rickdb1boat]

Re: HOT or NOT?

Ditto on the water pump! 180-190F still sounds high to me and 220 is out of the question, but maybe the Mercs run that high. I would think 160*-180* would be closer, but I may be wrong on that. The oil you are using is fine.. How old is the impeller??

 

[quantumleap]

Re: HOT or NOT?

A good stream at idle doesn't rule out a bad impeller. If it's old, it can become too flexible and not move as much water at higher RPM's.

 

[Searenity]

Re: HOT or NOT?

the boat and motor is 5 years old, I need to check the repair records to see if the impeller was ever changed, The stream is good(better then mine) thanks for the answers. I always try to look this stuff up first, but sometimes I just canr find the answers I'm looking for. Thanks again

 

[KCLOST]

Re: HOT or NOT?

The impeller is the first thing you should do...<br /><br />You want to make sure it is in good shape, start fresh...

 

[michaelbr1]

Re: HOT or NOT?

I agree with the others. I just put my boat back at the marina after being on the trailor for a year. Both impellors had been replaced within 6 months before I put the boat on the trailer, and the water was streaming out quite well when running. <br /><br />Once I took it out for a test run, one engine overheated while at 4000 rpms, and the other overheated at an idle. Had to snatch it back out and replace both impellors. Runs great now.<br /><br />BTW - changed the oil in your foot lately?