Thermonstat not opening......

[Kenny Guess]

I am having alarm issues on my 50 hp merc. 2 stroke....alarm comes on after 4-7 minutes of running but goes off when I idle only to come on again when I run again. Just took thermonstat out , put in boiling water but it did not open. Could this be causing the alarm problem? I want to take it out to try but the gasket is history, can I use permetex and leave the thermonstat out to see if my problem is solved? Can get new one and gasket next week......just want to know. What do you think? thanks, kenny

 

[Dan J.]

Sounds like the T-stat is shot/seized. Definitely replace ASAP. Yes, you can run it without the stat for testing purposes, but don't be terribly alarmed if it runs pretty bad and inconsistently. Your best bet is to run it after the day has warmed late in the afternoon as a cool morning WOT run could be quite a dog with a cold head. If it were me, I'd wait and replace stat and gasket. Good luck!

 

[Kenny Guess]

Thanks Dan for getting back....I am going to wait till tomorrow now. I am on the gulf coast so water temps here are already 75-79 degrees......

 

[Dan J.]

I just got back from Destin, FL on the gulf. Wish the ocean was a bit warmer. We had 72-73 degrees and a great time. Good luck on your rig!

 

[Kenny Guess]

Dan, I am on the coast in Diamondhead , just about 14 miles from the gulf. Bay St. Louis, Ms. Wish our water was as pretty as Destin.....that water is , I have read, like the top 3 in beauty from around the WORLD!

 

[Kenny Guess]

Well, changed the thermonstat, gasket and seal- for a total of about $ 45 and my alarm problem is fixed !!!!! I have been dealing with this issue for over a month but now it is done and I am a happy man again.Water pump is ready to be changed as general upkeep. I have to say that searching online helped me solve my problem. Never even knew outboards had thermonstats.....

PS Someone on this site sent me to BBC and that was most helpful............thank you.