"Don WA5NGP" wrote in message
om...
I've got a spare sending unit and gauge for water temperature. Being
the anal gauge watcher that I am I would like to mount the sending
unit on my 90hp Merc so I can get a better indication of engine
operating temperature before the alarm goes off. Any suggestions? I
was thinking of just putting it right on the water jacket on the power
head. I assume somewhere next to a spark plug would be a good place
too. It doesnt' need to dead accurate. I just want to get an
indication if things are working differently than normal such as if
something got plugged up with sand or something ugly like that. The
last time I was at the coast the telltale water tube clogged with sand
or seaweed so the whole time I was worried that I was about to
overheat when everything was ok the whole time except for that tube.

I know what you mean. First weekend with my "new" used boat and motor, the
tell tale quit working. I had no idea what to do except what I was taught
as a lad - don't run it if the water isn't streaming out. Now that I know
the alarm does indeed work I'm not as concerned, but have also learned the
"feel" of the head and leg at normal operating temp and can check that if
need be. I've also learned how to quickly clean out the tell tale when
needed. I also have a water pressure gauge so don't have to keep looking
back to fret over the tell tale. I've been toying with replacing the
pressure with a temp gauge, but...

As for your temp. sender. I think your ideas are good. You might check the
web page of the gauge/sender manufacturer. For instance, if it's a Teleflex
set up, I'm pretty sure their web site will have an installation manual for
the sender that will tell you where to put it on your particular engine.
Some of the other manufacturers of "universal" gauges have similar resources
on line.

Cam