Is this a thermostat?

[brother chris]

Okay, I have a 1978 55hp evinrude, and from previous posts, I have already changed the water pump and put the leg back on several times and no water comes out of the "p" hole. <br />After blowing air through the water tube with no avail, I decided to change/check the thermostat. <br />I took the back panel off(12-14 screws), and when I took it off, a red piece of plastic with a raised "x" on each side of it came out where the thermostat is supposed to be. There is a rubber gasket around it as well. It does not look like any thermostat I have ever seen. Even looking at the book, it looks different. Is this the thermostat? <br />I also have to replace the large gasket the goes between the back plate and the motor. <br />Anyways, can anyone tell me if this is the thermostat or not. <br />Thanks in advance.

 

[brother chris]

Re: Is this a thermostat?

Okay, I forgot something. I broke one of the bolts off when trying to take it out. <br />Also, I just went out and was trying to figure this out when I found a spring that was sitting by the motor. I assume, since it fits, that this goes over the red plastic(thermostat?)thing. <br />Also I have to go to work in an hour, so is it alright to just put the plugs back in and cover the motor. The boat is outside, but it is not going to rain for the next two days, which is when I have a chance to finish this. <br />Thanks in advance for the replies.<br />Bro Chris...

 

[jimchere]

Re: Is this a thermostat?

I have an '82 55hp 'rude and just changed out the thermostat. You removed the cylinder head cover, and that red plastic thing is actually the pressure relief valve. It should have a spring over it. The thermostat is located just below the pressure relief valve, and if you haven't worked on this motor before a previous owner may have removed it and not replaced it.<br />Basically, its a two part system under that head cover, consisting of (1) pressure relief valve/spring and (2) thermostat. The pressure relief valve should be inserted into the head with the beveled edge of the flange pointing forwards, and the spring goes over it as you put the cover back on.<br />Do you have a manual? If you have a Seloc, I can tell you what diagram and how to look at it.<br />Don't take chances with these parts, do it right, or you'll cook (destroy)your motor quick. You're also going to need a new head cover gasket, some sealant to put a new gasket on, and have to take some time to first clean up the mating surfaces (removing the old gasket material and sealant to make it smooth; be careful what tools you use as it is aluminum and you don't want to nick it).

 

[jimchere]

Re: Is this a thermostat?

Sorry, messed up the edit, read below post. Jim

 

[bubbakat]

Re: Is this a thermostat?

And please do not use silicone to seal those gaskets. Get you some liquid gasket sealer that comes in a little bottle or can with the brush to apply it with

 

[brother chris]

Re: Is this a thermostat?

Thanks for the replies.<br />After looking at it for a bit, I found that the thermostat was actually there. It looked like it had never been changed, and was part of the head. <br />It was all corroded, along with the entire inside of the head. I tested the thermostat in boiling water and it opened at around 180 degrees. That don't matter cause I am going to change it anyways.<br />What kind of liquid gasket sealer should I use for the head gasket. Does that really matter that much as I have all kinds of gasket makers at home.<br />I won't be able to finish this until Sat. since I have to work.<br />Thanks for all replies.<br />Bro Chris...

 

[brother chris]

Re: Is this a thermostat?

Just one more thing....<br />Before I put all this back together I plan on blowing air through the water hoses just to clear anything out that shouldn't be there. But can I hook up the ear muffs while the back plate is off and run the water? Can I also start the motor(and run water) while the cover is off to see if everything is working or will that wreck the motor? <br />And yes Jimchere, I believe it is a Seloc book, but I am not sure...I am at work right now.

 

[ob15]

Re: Is this a thermostat?

Just got done doing this on my 80 rude 50. The hardest part was getting the old gasket material off. Putting the spring back on the pressure relief was tricky also. Just take your time & you'll get it done. You can get the gasket sealing compound at the johnny rude dealer. That's what its called on the can. It a brownish liquid you brush on the gaskets. Good luck & enjoy.<br /><br />edit<br /><br />Do not run the motor with the head cover off. No water to keep engine cool. Will blow it up in no time.