The warning buzzer is intermittently activating on my 2006 Mercury Optimax Sport Jet 200HP and the smart craft guage is telling me "Reduce Throttle" and "Overheat". The temp readout is bouncing around from 131 to 158. The warning comes on at random times, from idle to WOT, and when engine is completely cool or warm. Temp readout on the smartcraft guage was 138 before I ever started the engine at 7am this morning. I also got "Check Engine" and "Pressure" warnings a few times shortly after the "Overheat" warning. So I am convinced that one of the 2 temp sensors on the cylinder head have failed and guessing that the guage must use an average of the 2 readings? Is that why it consistently reads high and sometimes high enough to alarm? Might the "Check Engine" and "Pressure" warnings be caused by the faulty temp sensor, or might I have a bigger problem than just a sensor?
Anyway, so I have ordered 2 new temp sensors and should have them any day, but when I took a look at the engine this morning, I could only actually see one of the 2 sensors and it looked pretty difficult to access. Is replacement of the temp sensors something I should be able to do myself (I am not a mechanic, don't know anything about working on boat engines, and don't have any special tools)? Can anybody give me simple instructions to do the replacement? Are there parts that need to be removed to get at the temp sensors? Are there any special tools needed?
Anyway, so I have ordered 2 new temp sensors and should have them any day, but when I took a look at the engine this morning, I could only actually see one of the 2 sensors and it looked pretty difficult to access. Is replacement of the temp sensors something I should be able to do myself (I am not a mechanic, don't know anything about working on boat engines, and don't have any special tools)? Can anybody give me simple instructions to do the replacement? Are there parts that need to be removed to get at the temp sensors? Are there any special tools needed?