Monitoring Engine Temp On Older Outboard

[74merc50]

Wondering if anyone has a cheap and dirty solution to monitor engine temp on an older outboard. I found a cheap temperature sensor and digital gauge on Amazon, for under 20 bucks. My only question would be where and how to mount the sensor. If these motors had a 1/8 NPT threaded port for a temp sensor, that would be incredibly lucky. If not, maybe just attaching it to the side of the water jacket with JB weld would work. Any thoughts?

 

[fastjeff]

You're lucky for many of them do have an 1/8 NPT fitting there

Jeff

 

[74merc50]

You're lucky for many of them do have an 1/8 NPT fitting there

Jeff

So now to drill down to a specific model and year, would any old school Mercury expert know where to find that port on a 1974 Mercury 50hp 4 cylinder (500)?

 

[racerone]

Look near the top sparkplug.----A .125 pipe plug is shown on many models !!