1979 Evinrude 115 overheating alarm

[Southporter17]

I recently aquired "Lily Belle" with no previous history accept that she is an ALL original, 1 owner, garage kept beauty. She fires right up and runs smoothly. We put in today and didn't get very far(2-3mins) before the overheating alarm sounded. When I looked back water was still being discharged. I shut it down, waited and restarted to see only mist/steam(no stream). Once I got her home and pulled the lower unit and disassembled the H2O pump I found that the impeller looked to be in good shape(flexible,no knicks or cuts). Ive ordered a water pump kit but I suspect that this is not the problem. If it's not the H2O pump what sould be my next step/steps?

 

[SparkieBoat]

Re: 1979 Evinrude 115 oreheating alarm

Re: 1979 Evinrude 115 oreheating alarm

t-stats and engine flush..but you may fix problem with new impeller..sometimes they look ok but have lost the strength in the paddles they need...also make sure you do not have a lean cylinder condition caused by a partially clogged carb.

 

[emdsapmgr]

Re: 1979 Evinrude 115 oreheating alarm

Re: 1979 Evinrude 115 oreheating alarm

Any engine will overheat if the cooling water won't recirculate back into the midsection. You can have great cooling water pressure, but if the water won't go through the thermostat housing, it will surely overheat the powerhead at idle. That housing has two thermostats, one controlling the temp in each head. If you knew which head was overheating, you would know specifically where to start looking. Pull that housing apart-you may find one (or both) of the thermostats are stuck closed. If you replace both stats and it still overheats, you will want to pull the heads and check the water diverters in the water jackets next to each cylinder, maybe even pull the head covers off and inspect for debris. There are two small pinholes in the thermostats plastic valve body which occasionally plug up with debris-they need to be open for proper cooling.

 

[Southporter17]

Re: 1979 Evinrude 115 oreheating alarm

Re: 1979 Evinrude 115 oreheating alarm

Thank you. I also need advice on how to remove a stubborn impeller from the shaft. Any input will be greatly appreciated.

 

[SparkieBoat]

Re: 1979 Evinrude 115 oreheating alarm

Re: 1979 Evinrude 115 oreheating alarm

I pry them up with a flat head screw driver and hammer if needed