1987-8? mercury 150 need module identified

[Tnscooter]

I just bought a Procraft with a 150 mercury black max xr2, there is a module just under #2 spark plug (top left looking at back) was wondering if anyone knew what this would be for, the wire that goes to it has been broken off the top, and has power to it when key is on, motor runs, havent had on water yet, Thanks, Scott

 

[gss036]

Re: 1987-8? mercury 150 need module identified

"under #2 spark plug (top left looking at back)". I take that as the starboard side head you are talking about. About the only thing I can think of that would be is the overheat sensor. Is it a round item w/1 wire? Where does the broken wire go to?

 

[Tnscooter]

Re: 1987-8? mercury 150 need module identified

There is a module that bolts into the head just below the spark plug, there is a bolt and nut incased in plastic on top of module with the wire connected, the bolt and nut have broken out of the plastic, what worries me is the wire has a posetive current when key on. Thanks, Scott

 

[Chris1956]

Re: 1987-8? mercury 150 need module identified

Scott, Temperature senders will ground when they detect overheat. Grounding completes the circuit to set off the horn or turn on the light. You should trace the broken wire back and see if it goes to a horn or other warning device.

 

[j_martin]

Re: 1987-8? mercury 150 need module identified

There should be a sender on each head. The one on the port head is the overheat (switch) and a black wire goes to the terminal block that has the oil warning wired to it. Grounding it should sound the alarm.

The one on the starboard head is the temperature gauge sensor, and has a tan wire that goes through the harness to the controll, through that to the harness on the control that feeds the instruments. Tan all the way.

The mounting could be reversed, but the color code stays the same.

hope it helps
John

 

[Tnscooter]

Re: 1987-8? mercury 150 need module identified

Thanks guys, Is the temp unit, man is quite a big mark up on those little items, was about 10 times what a car is, oh well to play we pay.