1970 115hp Evinrude

[rayodunne]

Awakening this motor from a sleep and so far have got spark on all four. I also sorted out the lower unit as the resistance test on the blue and green wires failed. Tonight I put gas and controls on the motor and fired it up and it ran great at idle.
A few minutes later I shut it down as I noticed fuel coming from the lower carb throat. Stuck needle is probably the culprit.
Anyway when I shut it down the heads smelled pretty hot and I was not able to keep my finger on one for more than a second. Before this test fire I did change the impeller so why would the motor get so hot? Water was being ejected at the prop so that tells me the thermostat opened or maybe I'm wrong?
This motor has no tell-tale but I plan on installing one as it has a threaded plug on the left head which enters the water jacket.
Any ideas?

 

[emdsapmgr]

Re: 1970 115hp Evinrude

Even though you have a good impeller, the engine will overheat at idle if the vernatherm (thermostat) does not open. If that stat does not open, cooling water cannot exit the block (circulate) and it will overheat. Pull the cover off the thermostat housing at the back of the exhaust adapter and replace the vernatherm. Also, make sure the nylon pressure relief valve is not deformed due to overheating. When you run the engine again, you can tell when the thermostat opens. Hold your hand behind the two exhaust relief ports. After a minute or so, water droplets will form on your hand, indicating the stat has opened. That's normal. You can install a tee into the block for a telltale. Most of them are in the exhaust cover. Make sure you loop any telltale hose up above the top of the engine, then back down. Also, there is a lower cowling restrictor nozzle you should probably add so that too much water does not exit the block throught the telltale.