Getting hot with earmuffs on

[Rippin_54]

Just getting 20 foot regal with 305, merc alpha 1 (1989) ready, put on earmuffs and let engine run for a while at just an idle, after about 15 min, i noticed the temp was getting high. I normally don't rev the engine when its on the muffs, but decided to give it a tad above idle, and the temp stopped rising. Had the impeller replaced 2 season ago, with maybe 20 hours use on it (not used much).And also a new thermostat last year.


Just wondering if this is normal, or i should be concerned about this. Original water pump on motor. I have rarely used muffs, so i'm not sure about this. I am thinking it should be ok when put in the water, but if this is the tell tale sign of a proplem, i would rather fix it before hand.

 

[Brentathon]

Re: Getting hot with earmuffs on

Was the boat used in saltwater, and is it raw water cooled?
I always make sure a little water is squirting out from the earmuffs (at all rpm's), and this way I know there is a little excess hose water.

 

[90stingray]

Re: Getting hot with earmuffs on

I would say impeller is weak and needs changed. Only cooling down when you rev it because you are spinning that impeller faster to do the work. Exactly how mine was till I changed impeller.

 

[Bondo]

Re: Getting hot with earmuffs on

Had the impeller replaced 2 season ago,

Ayuh,... But that's Still the 1st place to look in any Overheat situation...

 

[Brentathon]

Re: Getting hot with earmuffs on

Even before you remove the drive and replace impeller, I would do the easy stuff first; simply ensure the hose is supplying enough water.
Then, not sure what T-stat housing you have, but low-speed overheat can be cause from white plastic checkballs not seating well, expecially due to considerable corrosion on T-stat housing (I'm on my 3rd); that's also very easy to check.

 

[cr2k]

Re: Getting hot with earmuffs on

If the impeller is 2 seasons old it is due for replacement anyway.