Re: Yamaha 130 2 stroke 2001 alarm
The sensors are comprised of a plastic/rubber plug that is recessed right next to the cylinder heads and two wires with inline connections. You should be able to disconnect the sensors by means of the two wires that connect them back to the harness, just pull one wire to prevent the overheat throttle limiter circuit from closing. Now bear in mind, if your engine is legitimately overheating, you'll want to know it. In my case the engine block was not so hot that I couldn't put my hand on it while the engine was running, I knew that the cooling water was flowing around the jackets, and there was no significant difference between the two sides, so I felt comfortable that I was not overheating. You can disconnect one or the other to detect the sensor that is tripping at a lower temperature, and then switch the sensors by pulling the plug out of the cavity and switching the wires to determine if a known working sensor will alarm on either side. The shop manual I have indicates a turn on temperature of 183F to 194F for the sensor, and the test is to dip it in hot water while connected to a continuity tester to see if the circuit closes between 183F to 194F and opens again between 140F to 165F.
Good luck!