what is it

[jdb21867]

I have a 1986 40 hp Evinrude e40rcd , tiller handle . I t had a blown head gasghet . At disassembly I found a spring and melted goop in hole #1. Is it the thermostat or relief valve ??? What do they do and can I live without them ---why or why not ---thanx

 

[flyingscott]

That is the thermostat and a new one needs to be installed. Make sure you resurface the head as your motor probably overheated at one time. You may also want to look at the waterpump impeller. If the motor runs to cold you can get excessive carbon build up and plug fouling.

 

[Boobie]

What do the cylinders look like ??

 

[joereeves]

#1, "Spring & melted goop" is a spring loaded water bypass (nylon) valve. It is a needed component and the engine cannot do with out it. This allows water under high pressure to bypass the thermostat when needed.

#2, "Thermostat" is self explanatory, obviously needed.