I just got a new temp gauge for my boat and was surprised it did not come with a probe. It has the standard four posts on the back. I decided to attach the S post to the tan wire that goes to the alarm in the remote since that wire goes to the temp probes in the heads. I have power but the gauge won't give me a engine temp reading. I'm guessing this is not the correct set up. I have a 1988 150hp Evinrude 150TLCRD. Any help would be great.

Should have a tan with white stripe for gauge.

I put a gauge on my motor. I had to buy a probe separately like you will have to do (just make sure it is a match). My block had a brass plug in that was designed for a probe. put it in and wired it up. Should be pretty straightforward. Just have to find out where the probe is gonna go in your block.

I'm pretty sure the wire that goes to the warning is not the one you want. I think you should leave it be. I'll bet if you hunt around on your block, you'll find a place for the sensor.

Biscuits, I'm not 100% sure but I think this is your motor. #11 I think is the plug where you can install a sending unit. See if you can find that on your block.

http://www.marineengine.com/parts/johnso...mp%3B+Crankcase

It is a Klikzon switch with open points that close only on over temp. You are going to have to probe the water. That's all I got.

I think I have it figured out. I'm going to add a couple nipples to the P stream line, that way I can measure the water temp and I have room to install the probe. The probe is about 2 inches long and I just don't see a spot on the heads for it. I got to thinking what is it that is being measured? The water temp or the temp of the heads? I assume it's the water temp.

If you change your impeller every couple of years you don't really need a temp gauge.