Mercury 90HP Temperature Sending Unit Location?

[WildWillJAX]

I have purchased a 1989 90HP Mercury O/B S/N OC162559 Inline 3 cylinder. This motor has a overtemp warning and a low injection oil quantity warning system. There is a temperature gauge installed on the instrument panel but it does not work (12 volts is present at gauge with key on, but no continuity to ground). Isnt there a typical engine mounted temperature gauge sending unit to regulate electrical power to this gauge by varying the resistance on the ground terminal depending upon sending unit/cylinder head water temperature? If so, where is it found on the power head? My "CLYMER" Shop manual does not discuss this critical monitoring system or the component location and does not provide a wiring schematic for this circuit. <br />WildWillJAX@aol.com

 

[hondon]

Re: Mercury 90HP Temperature Sending Unit Location?

Temp guage kits as well as water pressure guage kits are add ons and not part of the stock engine.Thats why no mention in the manual.Those kits can come in a few different configurations but most will either replace the warning horn sender with a temp sender or place a temp sender into a plug at the top of your piston dome water cover.

 

[WildWillJAX]

Re: Mercury 90HP Temperature Sending Unit Location?

Thanks for the information