I need some help and guidance please. Just recently bought a new to me pontoon boat with a 1991 Johnson 90hp (model J90TLEIE). Took the boat out last week and the engine fired right up. However, after about 15 seconds of running at idle, the overheat alarm came on. Got the boat out of the water and home, hooked the water muffs up to it. The overheat alarm came on again after about 10-15 seconds. It has a strong flow of pee. I felt the cylinder heads while it was running. One was hot to the touch and the other not. I replaced the 2 thermostats, poppet valves and springs. One was working and the other was stuck open. With the new thermostats, both cylinders are equally as warm, not so hot that you want to immediately remove your hand. However, the alarm sounded again after 10-15 seconds. I disconnected the two temperature switches, but alarm continued.
I then bypassed the tan wire going from the alarm to the temperature switches and the alarm did not sound. Does this mean there is a short in the tan wire going from the alarm back to the temp switches???? Does anyone know if there is anything else that connects to this tan wire besides the temp switches that could be causing the alarm?? Any help would be very much appreciated. Thank you!!
I then bypassed the tan wire going from the alarm to the temperature switches and the alarm did not sound. Does this mean there is a short in the tan wire going from the alarm back to the temp switches???? Does anyone know if there is anything else that connects to this tan wire besides the temp switches that could be causing the alarm?? Any help would be very much appreciated. Thank you!!