Do I need this part? 1976 70hp Evinrud

[John90290]

Getting a 1976 motor to run after a few (10) years in storage is fun. She started right up, great idle but no water flowing so i killed the motor. Figure it's the impellar but pulled the thermostat housing to see if that was clogged. Well, no thermostat, which is not a big deal but the two plastic vlaves held down by the springs, (item 68 in picture) were totally melted.

A few questions:

What do these valves do?

If i'm running without a thermostat- which i do- do i need to replace them?

Any help would be appreciated!

 

[blouderback]

Re: Do I need this part? 1976 70hp Evinrud

You really should replace the thermostat. The engine was designed to run at a certain temperature, and if water is constatnly flowing through the block because the thermostat is not there, it will never reach proper operating temperature.

 

[tashasdaddy]

Re: Do I need this part? 1976 70hp Evinrud

replace the tstat, and the poppets. you need them for the motor to run correctly and at optimum performance. if the motor didn't need them, the bean counters would never let them spend the money for them. causes poor fuel burning, carbon buildup. excessive wear on the powerhead.

they are melted because the motor ran hot. i would check compression, as head gasket could be blown also.

 

[John90290]

Re: Do I need this part? 1976 70hp Evinrud

Just ordered the parts. Thanks for the help guys.

Compression was 110 on all three, so hopefully it was not too damaged by the overheat event.


-John

 

[samo_ott]

Re: Do I need this part? 1976 70hp Evinrud

That's one of the best titles ever!

"Do I need this part"?

Haha! It made me laugh

 

[F_R]

Re: Do I need this part? 1976 70hp Evinrud

Those melted pressure valves are a bit worrysome. Obvioulsy, the motor has been overheated. Even mild overheating on the three-cylinder motors can warp the exhaust cover plate and allow water to squirt in through the exhaust ports. When that happens, it is good-by powerhead. I suggest a replacement of the head gasket and exhaust cover gaskets is in order. And check for warping around the exhaust passages in the plate.