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Evanrude E15rcob

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(Thermostat Purpose)
(J. Reeves)

Many engines are considered high performance engines and demand a thermostat(s), and many smaller hp engines also require a thermostat for the following reason. 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 temperature to compensate for the distortion.

With the thermostat removed, the difference in temperature between the inside the cylinder and the water jacket quickly reaches a point whereas (in effect) you have a oblong piston running up and down a round cylinder, or vice versa. Bottom line is without the thermostat, the piston and cylinder wall could be damaged in a short period of time.

The thermostat in your car isn't there simply to have the heater function properly..... think about it.

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Fuel that is going from the liquid state to the gaseous state needs heat.-----So the thermostat makes the motor run warmer / better at idle and trolling speeds.----The CAST IRON cylinders also expand properly to give the piston the proper clearance / fit in the cylinder.-----Just looked at a 1961 model 10 hp the other day.-----Showed owner that thermostat was missing.----And there are hundreds of these motors running with thermostat missing or stuck open !!
 
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Excellent, guys. I really thought cold was better when I was young. The motors I started out with had NO thermostats. Many thermostats get plugged or stuck partially open with crap. It is key to keep proper operating temps because aluminum has a different "expansion rate" than that cast iron sleeve, or in the case of other outboards......cast iron block, (like my Suzuki Spirit 16 hp). So proper clearance is maintained when operating temps are correct.
 
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joereeves said:
********************
(Thermostat Purpose)
(J. Reeves)

Many engines are considered high performance engines and demand a thermostat(s), and many smaller hp engines also require a thermostat for the following reason. 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 temperature to compensate for the distortion.

With the thermostat removed, the difference in temperature between the inside the cylinder and the water jacket quickly reaches a point whereas (in effect) you have a oblong piston running up and down a round cylinder, or vice versa. Bottom line is without the thermostat, the piston and cylinder wall could be damaged in a short period of time.

The thermostat in your car isn't there simply to have the heater function properly..... think about it.

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Click to expand...
I understand thanks I will replace it
 
timguy said:
Excellent, guys. I really thought cold was better when I was young. The motors I started out with had NO thermostats. Many thermostats get plugged or stuck partially open with crap. It is key to keep proper operating temps because aluminum has a different "expansion rate" than that cast iron sleeve, or in the case of other outboards......cast iron block, (like my Suzuki Spirit 16 hp). So proper clearance is maintained when operating temps are correct.
Click to expand...
thanks I will order a new one problem solved
 
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