89 xp 150 overheat (solid tone) alarm

Josh H

Recruit
Joined
Apr 1, 2013
Messages
5
After a normal warm up period of 5-10 minutes in the water I get a solid horn. In the driveway I checked temps with a infrared temp gauge,(no horn) the port side peaks at 145 degrees F and the starboard side at 175 f. The starboard side stays 30 degrees hotter from warm up thru shutdown. Should I do a theromstat on the hot side?
Thanks, Josh
 

71Windsor

Petty Officer 1st Class
Joined
Jun 25, 2008
Messages
286
Re: 89 xp 150 overheat (solid tone) alarm

I'd check and replace both thermostats. Sounds like the hot side may have clogged passages or a t-stat sticking partially. When's the last time you checked/replaced them? What are your conditions you operate in? Lake? Salt water? Low water with grass or mud? Salt is havoc on my thermostats. I pull mine every year clean the cavity boil them off and scrape any excess buildup out with a good blast of water or compressed air to get it all. Me personally running in the salty waters here I check every year replace every third regardless. 50$ in parts and 20 minuets is much less of a headache then a complete overhaul and possibly new heads.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 89 xp 150 overheat (solid tone) alarm

That engine will set a hot horn when the head temps get up to 203 degrees. The horn will shut off when the temps go back down below 175-which is still way to hot. Your engine should run between 143 and 155 at idle. Probably just a stuck stat. Agree on the stats, replace them both. When you have the thermostat housings apart, also check the nylon pressure relief valves to make sure they are not heat-deformed. Hopefully, this will cure your overheating. If that does not take care of the overheat, you may want to pull the hot head and check the cooling passages around the cylinder liners. Specifically, the placement of the rubber water diverters. Make sure there is no restriction in the block by those diverters.
 

Josh H

Recruit
Joined
Apr 1, 2013
Messages
5
Re: 89 xp 150 overheat (solid tone) alarm

Thanks for the advice, I will order new t-stats and try it.
Thank you, Josh
 

89renken175

Cadet
Joined
Feb 1, 2012
Messages
13
Re: 89 xp 150 overheat (solid tone) alarm

If the thermostat don't fix it, I would check the temp senders. Good luck!
 
Top