Thermostat

[slats]

I have a Johnson 112HP. In June of 1999, I had the thermostat replaced because the engine was running hot. Since that time I have used it four times. I fish in saltwater so I flush and clean after each use, cover it and park it in my yard. In getting it ready for my first trip, the engine started running hot again. Water was coming out okay. When I called the repair shop I took it to in '99, they told me the thermostat needed to be replaced again, that when it sits up for long periods of time, the thermostat can go bad. I have been told to just take the thermostat out and throw it away. Anyone have this problem?

 

[12Footer]

Re: Thermostat

Yes, the T-stats fail when they sit dormant for long periods of time..In salt water, they sieze-up in less than a month at times.<br />They are made outta brass and copper,but still corode into closed.<br />DO NOT pull it out and leave it out. It's fine to do for testing, but do replace it.<br />If left out, the head gets unequal cooling,and can warp,crack,or something else nasty.<br />But one 20 minute test run is fine.<br />Luckily, they don't cost a lot. I keep a spare in my bilge.<br /><br /><br />------------------<br />the Early bird get's the worm...So, he don't have to stop for bait.

 

[slats]

Re: Thermostat

Thanks for your reply. Is it easy to replace? I am not good with repairs. They charged me $300.00 to replace the last one.

 

[JB]

Re: Thermostat

Howdy, slats. 12Footer's advice is good. If you get charged $300 for replacing the Tstat, it seems worth while to spend $30 on the correct Clymer manual and learn how to do it yourself. Then, if needed, you can change it "out there" and save yourself a lot more than $300.<br />Good luck.<br />JB

 

[12Footer]

Re: Thermostat

I hate to tell you this,slats. But under no cir***stances, go back to that shop!<br />I wouldn't even get the shop manual from him,even if he was the last guy in town (internet is a good source).<br />300 smackerz for a T-stat change-out is total theft!<br />They are a breeze to change out in most cases.<br />Less than an hour in all cases.Both mine, less than 5 minutes... But do get the shop manual. It'll payu for itself on the first job.<br /><br /><br />------------------<br />the Early bird get's the worm...So, he don't have to stop for bait.

 

[Dhadley]

Re: Thermostat

Hey Slats, just a thought -- With the "tuned" exhaust bubble on the 112, it's pretty tight to get to all 3 t-stat housing bolts. They may have pulled the powerhead to drop the pan so they could get at the bolts. Especially if some were "frozen". That would explain the extra time and charges. <br /><br />I'm kinda surprised you have so much t-stat problems. Maybe I'm lucky but it's just not something I've had problems with on a V4.<br /><br />Good luck!

 

[alvinmh]

Re: Thermostat

I got an Evinrude 1994 V-4 120 hp with the same problems. Guess I will have to change thermostats every year. ($12.50 each)<br /><br />------------------<br />alvinmh

 

[Chris Wilson]

Re: Thermostat

I've commented to others that had thermostat problems and I agree with those who replied that you should not run for an extended period without one. I would not know enough to argue about uneven cooling and warping of components but I do know that it could very well change the performance characteristics of your motor - at all speeds.<br /><br />We had a thermostat stuck open on our 1991 Evin. 40 (didn't know it)and the motor ran poorly. We could use it, but it never seemed right. Couple that with the temperature of the water varying (we live in Michigan and boat in Lake St. Clair which can be a fairly warm lake - until you take the boat into the feeding channels coming from Lake huron big cool down and temperamental engine.)<br /><br />Anyway, once we figured out the problem (the manual gave us some indications on how important temperature is i.e. don't let it get too hot - or too cool) we changed the thermostat and the perfomance improvement was dramatic. I was stunned.<br /><br />So, my advise is that you can probably test without, but don't plan on regular use without one. And if you are testing without one, and your engine does not seem quite right, put in a good one and try it again and see how you engine runs before you start serching other reasons for a rough running engine.