My 225 ETec sounded a high temperature alarm as it approached 200 degrees. Replaced a bad thermostat, still ran on the hot side. Replaced the pressure blow-off valve and still on the warm side. Running at 1800-1900 rpms temp can get up to 197. Backed down to idle speed at 500 rpm temp reads 164.
Same thing happens to my 2009 225 etec. It happens sporatically while trying to get up on plain with a loaded boat. I did the following and have not been able to figure it out.
- Changed thermostats
- Changes pulpit valve
- Changed water intakes to higher flow
- Added water pressure sensor
- Checked and changed the thermal grease on temperature sensors
- Changed impeller
I am out of warranty and since it does not happen often I have not wanted to take it to a mechanic.
Let me know if you get any insight.
If you only changed impeller, you may have to change the complete water pump kit as any grooves that you can feel with your fingernail, lower the amount of water flow to the engine.
There may be a lower pressure spring for the blow-off valve that helps in many situations as do larger water pickup screens if disturbed water is coming off your transom and keel.
"There is never just one thing wrong with a boat";
-- Travis McGee, main character in a book series by John D. McDonald
The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.
The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.