20 hp thermostat

Landlocked_

Recruit
Joined
Jan 20, 2011
Messages
3
Yesterday on short trip that became shorter when I began to notice unusual amount of steam coming from the water discharge of my '86 20 hp Evinrude, appears to be plenty of water moving, but it seemed to be getting too hot, I'm guessing thermostat has failed or is obstructed. Does the entire head have to come off to investigate? The bolt pattern suggests the T-stat housing should come off separately, but there doesn't appear to be a seam between said housing and the head:confused:. Any help would be appreciated, thanks in advance
 

RadarRick

Petty Officer 2nd Class
Joined
Jun 30, 2010
Messages
189
Re: 20 hp thermostat

I'm not totally certain about your motor, but there are usually 2 screws holding the thermostat housing in place. Once the screws are removed, you should be able to carefully pry off the housing and remove the thermostat.

Once you have the housing removed, and have the thermostat out for testing, you can run the motor for a few seconds to backflush any crud from the area around the thermostat.

Was there good flow from the tell tale? If not, you might check the water pump.
 

Landlocked_

Recruit
Joined
Jan 20, 2011
Messages
3
Re: 20 hp thermostat

I'm not totally certain about your motor, but there are usually 2 screws holding the thermostat housing in place. Once the screws are removed, you should be able to carefully pry off the housing and remove the thermostat.

Once you have the housing removed, and have the thermostat out for testing, you can run the motor for a few seconds to backflush any crud from the area around the thermostat.

Was there good flow from the tell tale? If not, you might check the water pump.
Ty sir for your prompt reply, I did however have a recollection of an old motor I had many moons ago that made me take a second look. And I found that it was not the "head" but a water jacket/plate, I have gotten it off, although rather nasty looking it does indeed open and close. Well simply because of the appearance and the fact that i'm going to have to get a new water jacket gasket, I'm going to replace it, but it would seem that I need to get on into the water pimp and inspect that, to which I will go ahead and replace that as well while I'm in there. The motor is new to me and I have no "true" history on it, better safe than sorry in my opinion, small price to pay for peace of mind. To answer your question, yes I seemed to have good water flow out of the tell tale as well as the discharge at the rear, but apparently not enough to please the motor.
 

Cofe

Lieutenant Commander
Joined
Apr 23, 2009
Messages
1,883
Re: 20 hp thermostat

You will have to remove the cylinder head cover. Here is a pic.

As far as the tell tale getting steamy, it may be that the exhaust cooling water baffle or gaskets are bad. This would let exhaust into the cooling water system and make the telltale appear steamy.
 

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