Evinrude / Merc/ Johnson run without thermostats..

[w2much]

I live in Southern CA. Here and again I pick up old outboard motors and as a hobby get them running again. Often they don't pump water or show no sign of it as they have been stored for a while, turns out that often the thermostat is just stuck. Although I have replaced a few impellers I never replace the thermostats, just remove them and run without. What are your thoughts on this? Any knowledgeable reply is appreciated.

 

[walleyehed]

Re: Evinrude / Merc/ Johnson run without thermostats..

without the stats they run too cool...they never reach the temp in which the tolerances are correct such as piston to cylinder fit. It also adds to high carbon build-up.

 

[rodbolt]

Re: Evinrude / Merc/ Johnson run without thermostats..

and the t-stat is normally part of the pressure control system. most loopcharged motors running cold dont run well, especially at idle.<br /> its just to easy to fix it correctly. are there times when I will cut the poppets out and reinstall the body? yep, mostly for beach launched net skiffs. some of my mullet netters that spend a lot of time in 2ft of water get modified as well. but as a general rule if ya repair it the way it was designed it runs better longer. it also has a tendancy to keep moisture from collecting in the crankcase for those that boat in high humidity areas. one of the draw backs to carb venturies is the cooling effect of the air downstream of the venturis. it has a tendancy to drop the moisture out of the air. in certain cases its bad enough to allow carb icing.