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Evinrude how to remove thermostat

jackman

Contributing Member
I have a 1983 15hp Evinrude.

I have a 1983 15hp Evinrude. When I checked the workshop manual as to how to remove the thermostat it seemed an easy job. Undo seven bolts and take of the cylinder head cover BUT the bottom bolt is below the level of the casing the engine sits in and is inaccessible. Surely you don't have to lift the engine clear of the casing to do this as there would seem to be a lot of undoing to be done OR is there a special spanner? Any advice gratefully received.
 
Thermostat removed. I first of

Thermostat removed. I first of all drilled through the casing with small drill which didn't quite line up with the bolt head but by measuring the distance it was out by I was able to get lined up on the bolt head with a larger drill and finally ended up drilling a 17mm hole through which I could fit a socket. The fuel line is very near the bolt head so I inserted a strip of metal to protect it. The hole also pushed up against the base of the cover latch but there was just enough room. With all the bolts out I couldn't draw out the cylinder head cover but found it was being held by the thermostat spring but I sprung it free by inserting a thin bladed screwdriver. My local dealer advised not fit a new thermostat saying there were more trouble than they were worth.
 
"Install a new thermostat, unl

"Install a new thermostat, unless You think Your 'dealer' is more knowledgeable than the people that designed the engine. They put it there for several other reasons than just giving You a head ache!
Use Sealing Compound (OMC/BRP) on all screws and gasket."
 
I'll take your advice Mort

I'll take your advice Morten and fit thermostat. I may have been told to leave the thermostat out because we don't get extremes of hot and cold weather here and I only have the outboard as a get me home if my Mercruiser engine fails. It's never in regular use.
 
"(Thermostat Purpose)

"(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 temperture to compensate for the distortion.

With the thermostat removed, the difference in temperture 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.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay store at:

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store"
 
"Joe, Thank you for your very

"Joe, Thank you for your very informative reply. I've already ordered a thermostat so I'm OK on that score. Thanks once again for your advice."
 
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