Thermostat Issues

Slateroc24

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Jul 4, 2010
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15
I have a 1996 Evinrude 60hp on the back of a Lund 16ft. Does anyone know does the thermostat have a temp to it like a automobile does? I run the boat the the summer 90% of the time where the water is 70 or above. I pulled the thermstate out last summer cuz I was having a brain fart and never put it back in. How important is it to put it back in if I don't do any spring or fall fishing??
 

Daviet

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Sep 24, 2008
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8,958
Re: Thermostat Issues

The engine would run without the thermostat, but fuel consumption and the idle may be affected. the engine would operate better at temp.
That being said, there are alot of engines running without thermostats in them.
 

Cofe

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Apr 23, 2009
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1,883
Re: Thermostat Issues

Yes thermostats for boat motors have a temperature range like automotive ones.

1. Without a thermostat in a motor will foul the combustion chambers up faster than with one. The higher temperatures with a thermostat help burn out oil deposits.
2. You will get poorer gas mileage without the thermostat.
3. The pistons may score or lock up, a condition called "cold seize". This can happen if you go to WOT before the motor has had time to warm up.
4. Plugs will foul
5. Engineers have designed the motor with a thermostat. So it is best to use them.

Welcome To IBoats!
 

Slateroc24

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Joined
Jul 4, 2010
Messages
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Re: Thermostat Issues

Thank you both, forums are by far my favorite problem solving tool...I really have no reason not to install one beside the fact that I hate...HATE taking my stuff to anyone to work on it. I've looked at the microfiche of the thermostat and it doesn't look to tuff. So after I complete the job, when I fire it up I won't see any water coming out the exhaust till after it warms up and the stat opens right?
 

Cofe

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Re: Thermostat Issues

A thermostat lets water enter the cylinder head after the motor has heated up to operating temperature.
A thermostat has no effect on the tell tale water stream.
A tell tale water stream only tells you if the water pump is working.
 

bob johnson

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Feb 25, 2009
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4,306
Re: Thermostat Issues

A thermostat lets water enter the cylinder head after the motor has heated up to operating temperature.
A thermostat has no effect on the tell tale water stream.
A tell tale water stream only tells you if the water pump is working.

the tell tale water stream comes from the motor!!! not directly from the water pump...so if you are getting water coming out of the tell tale then you know the water pump is working and you have water running through the motor....

maybe not the heads, but at least into and out of the motor


bob
 

Cofe

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Apr 23, 2009
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1,883
Re: Thermostat Issues

the tell tale water stream comes from the motor!!! not directly from the water pump...so if you are getting water coming out of the tell tale then you know the water pump is working and you have water running through the motor....

maybe not the heads, but at least into and out of the motor


bob

My point exactly Bob, The tell tale will never tell you if your thermostat is bad.
The tell tale only tells if water is traveling from the water pump through the motor.........BUT not the head.
The Thermostat only regulates flow through the head. The head has a sensor on it to set the warning alarm off, or put the motor into SLOW mode.

People think their motor is not overheating because they have a good tell tale flow. To the contrary, the thermostat could be messed up and wont let water circulate threw the head, and you have a full bore water flow from the tell tale.
 

bob johnson

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Feb 25, 2009
Messages
4,306
Re: Thermostat Issues

after posting about the head not getting water until the thermostat opens, i got wondering about my fitting that I run my water pressure gaquge off of...i was THINKING that was coming off the head....went to look....

sure enough the port that feeds my water pressure guage on in the middle of the head off center!!!

water run to this instantly!!!because i get water pressure readings as soon as i start my motor...

interesting....I imagine it is a small passage though.....and just feeds the fitting...


bob
 

Cofe

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Apr 23, 2009
Messages
1,883
Re: Thermostat Issues

I see what you mean Bob,
The thermostat has a small hole or notch in it so the pressure is equalized between the cylinder water ways, and the head.
This has nothing to do with temperature though.
If you had a pressure gauge on the head, it would be close to the same pressure as the water pump.

Now if you had a temp gauge on the head, and on the cylinder water passages, the temp would be different until the thermostat opened, and then both would be constant.

Now if you throw a Vernatherm into the mix, it all changes.
 

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