Thermostat question

[iggyw1]

O.K. guys,

I finally got my problems solved with the water pump that would not pump properly. I now have a decent flow thru the cooling system. I removed the thermostat and I have a real good flow thru the system. I know it's not good to run it without the thermostat in it. I tested the thermostat and it opens in hot water and closes when the water cools, but my manual has no indication at what temperature the thermostat is suppose to open at. It tells how to test it by hanging it by a string and dipping it into 'hot' water that is not yet boiling and see if it opens, but no temp. is written anywhere that I can see in the manual. It must have a certain temperature at which it is suppose to open.

Also, are there differant temp thermostats that are available for the same motor, such as a 180 degree or a 190 degree thermostat?? What should mine open up at? It is a 1962 Evinrude, 40 h.p model # 35933.
Thanks.

 

[F_R]

Re: Thermostat question

140-145 degrees. Um, just wondering, are you sure you had a problem? It is not supposed to have "a good flow" when the 'stat is closed--only a light mist. Under that conditon, the water goes back to the pump for recirculation. Furthermore, with a good water pump and cool water, it may not open at all at slow speeds because it doesn't get warm enough to open it (the water is recirculating and mixing with some cool lake water as it does)

 

[iggyw1]

Re: Thermostat question

F_R,

I ran it yesterday without the thermostst, and I don't think it ran hot enough. First of all, the water came out at a real good rate (too good I am thinking) and it cooled the engine too much. And the biggest problem I had was a 'fuel' rainbow around my motor as I moored at the dock when I came in from the lake and also around and from the motor while anchored out on the lake. I never had this problem with this motor, and I attribute this to the fact the motor did not warm up hot enough. Do you think this could cause the fuel not to burn properly and run out from the exhaust under water?? Or do I have a fuel leak now that I never had?

The thermostat is going back in. I probably will try the old one back in th motor again. It probably is not getting too hot. I can hold my hand on the head while it's running, then when it just starts getting hot to the touch, it cools down as more water is discharged thru the outlet where it comes out at. That may (I hope) get rid of the fuel rainbow??) You are probably right "do I have a problem at all". I probably do not.
Thanks.

 

[iggyw1]

Re: Thermostat question

I put my thermostat back in and the motor ran great with no unburned fuel around me at all. New question now: There was a "spray" of cooling water exiting the rear of the motor, which I understand is the norm for my motor. (40 hp evin. model 35933) and also what looked like a steam vapor. I thought for a moment that the motor was running much too hot. I felt the water spray and it was pretty warm but not hot. I took my motor cover off, felt the heads and they were cool to the touch. I was just wondering if the discharge looked like it was a steam vapor as it came out due to the cold temperature of the lake water? The water temp today is about 50 degrees Far. Thanks for your thoughts on this.

 

[Chris1956]

Re: Thermostat question

Stick a meat thermometer up the spitter. The water should hit about 140*F when the motor is warm. some steam is normal, especially on cold days.

 

[iggyw1]

Re: Thermostat question

Thanks Chris. Next time out on the lake I will definately do that. I figured the vapor (steam) I was seeing was pretty much the norm, but I attributed to the cold water temp. Didn't really think of the outdoor air temp. The last time I went out it was somewhere about 49degrees outside and water temp was about 50*F. I will get a meat thermometer tomorrow (or maybe the wife has one somewhere already). Thanks for the tip

 

[slate1234]

Re: Thermostat question

I had a similar thing going with a 6hp johnson, it pumps water like you wouldn't belive I replaced the thermostat for what it cost and it didn't look that good, I ran it in the test tank for 20 mins and I could hold my hand on the head for a good ten seconds,View attachment 172152View attachment 172153 I took the termostat of the BBQ and tried that lol but it worked

 

[iggyw1]

Re: Thermostat question

Slate,

I think I have my problem solved. I read your post, and I really never heard of a BBQ having a thermostat. That is a new one to me!! And you say it fit your outboard motor?? LOL That's wierd. Why would a BBQ have a thermostat? Never heard of it in my 63 years.

 

[slate1234]

Re: Thermostat question

well iggyw1, hear it is View attachment 172223View attachment 172224View attachment 172225,and we nned them in the uk we only get the sun twice a year so we need to know when the meat is cooked lol:facepalm:

 

[Rick.]

Re: Thermostat question

Slate,

I think I have my problem solved. I read your post, and I really never heard of a BBQ having a thermostat. That is a new one to me!! And you say it fit your outboard motor?? LOL That's wierd. Why would a BBQ have a thermostat? Never heard of it in my 63 years.

Big difference between a thermostat and a thermometer. I have to say I've never seen a BBQ thermometer that works! But it appears slate has one as it is zero'ed. Mine never go back to zero after the first year. Rick.

 

[iggyw1]

Re: Thermostat question

OK Slate, I see what you are talking about now. That's what we call a thermometer here in the states. LOL Yes, I have seen them on plenty of BQ's. What I was talking about is a THERMOSTAT. Google it and you will see why I said I never saw one on a BQ. LOL. It opens and closes to let water flow through a cooling water passge way, whether it is on an I/O, outboard motor or in a vehicle on the road. We just call things different names in different parts of the globe I guess. Thanks for the reply on it though.