Black max temperature sensors

[cam1399]

I have 2 sensors. One on port side with a stud the one on starboard has a wire attatched to it with a coil of wires. Which is for the alarm and which is for the gauge? Thanks

 

[Dukedog]

starboard is alarm.. port is gauge...

 

[cam1399]

I’m gonna install a gauge. Is the port side sensor a 2 wire? Mine is broke

 

[cam1399]

 

[Dukedog]

since that one looks like it reads actual water temp... it should be just one wire.. sensor grounds to tha block.. alarm should be one wire also.. my old age is settin' in!

must be an older merc with two piece heads..

 

[cam1399]

It’s an 84 150. Couldn’t find one with the smaller thread pitch. Will keep looking thanks

 

[Dukedog]

was that one on tha motor originally?... don't remember merc ever havin' a production "water" readin' temp gauge???..only after market stuff.

 

[cam1399]

It was on it when I got it. I took it off and it looks like it just touches the block. Doesn’t look like water comes through it.

What wire does this use to go up to the front of the boat

 

[cam1399]

 

[cam1399]

 

[Dukedog]

it will still use only one wire... what does tha one on star. side look like? should be a tan wire for gauge...

 

[cam1399]

The one on the starboard side is a tan wire. I traced it to the controls for an alarm.

Is there a wire in the factory harness for the port side for a gauge?

 

[Dukedog]

over temp should be a tan/blue.... in tha early days merc did some confusing things with tha tan and tan/blue.. at one time they were both tan (very early on) till they added tha blue tracer to tha alarm wire....

 

[Dukedog]

tha gauge at first was a very little used option... if there is a tan/blue in tha harness you can use it for tha alarm.....

 

[cam1399]

The starboard side sensor went to a junction block with a tan wire that runs through the harness connector

But I couldn’t find anything for the port sensor. I see a pinkish bullet connector on the starboard side of the harness that could have been ran at one time but wasn’

 

[Dukedog]

are tha sensors held in with a 2 bolt triangle shaped bracket?

 

[Dukedog]

that may be tha gauge wire.. most harness's had a spare tan for tha gauge that had a bullet connector on it.. if continuity checks from end ta end jus use it for tha gauge...

 

[Dukedog]

justa note.. most metal reading marine temp gauges are not very accurate.. best to rely on tha over temp alarm and water pressure gauge.. you need ta use a temp gun to determine jus how accurate tha gauge is.. ya may be one of tha lucky ones!

 

[cam1399]

Yeah both sensors are held in with a bracket with 2 bolts. The starboard pushes in with a rubber grommet and has a coil spring on it. The port side is 1/8 pipe thread with the same kind of bracket.

I’ll trace down that wire and see if it’s open. I’d say it is. Thanks