Mercury 90hp 3 cylinder temp sender

[Schnidly]

Can someone tell me at what temperature my temp sender will send an alarm to my warning horn? I tested it in water and did a continuity test and it varied between 170 and 190 degrees. The part number for my temperature sender is 78799 and the serial number for my mercury 90hp 3 cylinder outboard is 0B302485. Im replacing the thermostat, poppet valve and the alarm sender to rectify an overtemp alarm. I already replaced the water pump and have a great pee stream from the outboard. I get the over temp alarm, long beep after running for a few minutes.

 

[Texasmark]

195F and resets at about 175. Stat on that engine is 143F. At about 2500 rpm the pop off valve opens and bypasses the stat with a much larger hole and just lets ambient water free flow. If you can't run at low speeds without the alarm but can get on plane and it quits after a couple of minutes and then re sounds when you get back to slow speeds, your stat is stuck shut. That's how I find my bad stat the first time I took my newly purchased used boat out. If ok at low speeds but sounds at high speeds the pop off is stuck shut.

Mark