1990 Evinrude 70hp thermostat

[tangles]

Hi my 1990 evinrude vro seems

Hi my 1990 evinrude vro seems to get very warm when flushing and the beeper has gone off twice while cruising along.I have now taken the thermostat out and it seems to be running a lot cooler .Is it ok to run them without the thermostat ??


Tangles..........THANKS.....

 

[sparky]

It is not a good thing to run

It is not a good thing to run an outboard with a cooling system that is not up to par.You are best to install a new thermostat and to check bypass valve operation and verify that head gasket is not starting to fail.

 

[joereeves]

"Tangles.... Your engine is co

"Tangles.... Your engine is considered a high performance engine. The pistons actually distort/twist off round when running. The thermostat is required to keep the outer wall surrounding the steel cylinder, and the cylinder wall itself at a temperture to compensate for the distortion.

With the thermostat removed, the difference in temperture between the inside of the cylinder and the water jacket quickly reaches a point whereas (in effect) you have an off round piston running up and down a round cylinder. Bottom line is without the thermostat, the pistons will be damaged in a short period of time.

From what you've had to say, assuming that the compression is normal, it's obvious that your water pump is failing and should be replaced.

Joe

"