cooling question

[joho5]

1988 Evinrude 25hp. I ran my motor today and everything appeared to be working correctly. There was a stream coming ouf of the tell tale, there was water coming out of the other outlet (from the tstat), but the water was steaming a little bit. I could touch it but about 1-2 seconds. It was pretty hot, but not boiling hot to where it would physically burn your hand. It just seemed a little hot to me.

I am going to change out my impeller, because it is due, but should I just replace the tstat as well?

how hot should the water be coming out?

thanks

 

[Mas]

Re: cooling question

how hot should the water be coming out?

The engine temp should be between 125-160 degrees F. Idling about 140 degrees. However, measuring the temp of the tell-tale water is not a good indicator and should not be relied upon! You can buy a cheap infrared temp gauge that will measure the engine temp at the top the the head.

Harbor Freight has some the are cheap and work OK.


MAS

 

[1946Zephyr]

Re: cooling question

You can test your t-stat in a pan of water on the stove to see if it opens up, when the temperature of the water goes up. If it opens up okay and it's in clean condition, then I would say it's okay to re-use

 

[tashasdaddy]

Re: cooling question

if you run salt water change it.

 

[joho5]

Re: cooling question

Im not testing the tell tale, because its obviously always the same temperature. I am talking about the water that comes out where the tstat lets it through. It might be the correct working temperature, but I was just thinking it seemed a little hot. A strong stream out the tell tale says the impeller is functioning correctly though right? I will pull the tstat and test it and see if it opens up.

thanks.

 

[tashasdaddy]

Re: cooling question

if you are talking about he exhaust relief port on the back of the leg, that water is always going to be warmer. why because it is mixing with the exhaust coming out of the cylinders. coming into the exhaust housing.

also the tale tell gets warm also when the tstat does not open.

you can hold your hand in the tale tell stream and feel when the tstat opens and closes.

 

[joho5]

Re: cooling question

alright, that makes sense now. I bet everything is working fine. So its normal for the water coming out of the exhaust port to be steaming (smoking minimally)?

So with everything installed and working, what is the best way to tell if your engine is cooling to the correct temperature?

also, when I am testing it by the tell tale, the water is cooler when the tstat opens, and warmer when it shuts?

thanks, this helps alot.

 

[ezeke]

Re: cooling question

...... the water is cooler when the tstat opens, and warmer when it shuts?...

No, the tell-tale stream water is warmer when the thermostat opens, allowing the heated water from the cooling passages of the engine to escape.

When the thermostat is closed the water that is discharged from the tell-tale is bypassing the engine's cooling circuit.

 

[tashasdaddy]

Re: cooling question

best way to tell, http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93983 i keep one of these in my boat bag. running temp 140-160.

 

[joho5]

Re: cooling question

so is that thing infrared?

and you measure the block, or the water?

thanks

 

[Rick.]

Re: cooling question

Right at the top of the cylinder head. Rick.