What does the pressure relief valve in my 50hp 72 evinrude do?

[kippstakes]

Just wondering how the pressure valve in my cooling system works, and its purpose. Novice question I know.
Thanks

 

[175se]

Re: What does the pressure relief valve in my 50hp 72 evinrude do?

the tstat is what controls idle temp but when the engine is running at speeds it cant supply enough cooling, the increased pressure from the pump moves the valve off its seat thus supplying the water volume to cool the engine. (usually above 1800-2000 rpm)

 

[Joe Reeves]

Re: What does the pressure relief valve in my 50hp 72 evinrude do?

In agreement with 175se.

 

[kippstakes]

Re: What does the pressure relief valve in my 50hp 72 evinrude do?

Perfect. Thank you.

 

[Vintin]

Re: What does the pressure relief valve in my 50hp 72 evinrude do?

I didn't know that was how the cooling system was designed.

I have a question:

Once RPM gets to 1,800 to 2,000 and the valve moves off of it's seat, does it mean that the motor is now running with no temperature control at all(like my 1957 35hp RDE), or does the thermostat still play somewhat of a role in controlling motor temperature. I find it an interesting design and one that may save an engine if a thermostat were to fail in the closed position. Of course if the valve were to get stuck open than there would be no low RPM warming up temperature control.

I'm picturing the two water flow paths as being parallel and the thermostat still having a minor influence at higher motor RPM's.

Thanks.