Robert:

With clean heat exchangers my 6-71N run about 180 to 185 degrees. As the
heat exchangers gradually achieve a thin coating of salt the temperature
will climb to 190 or a little higher. In the Chesapeake you have to clean
the heat exchangers every three or four years. My temperature alarms go off
at 205 degrees.

Hope this helps

Frank Burrows 1979 43' Viking MY  Piney Narrows Marina  Chesapeake Bay

I'm pretty sure 170-190 is okay. After all there have been millions of
these and they didn't all turn up their toes and die because they weren't
kept within 5 degrees! Personally, I use a 170 degree thermostat which
generally keeps the temperature about 175. The previous one was 180, but
when it went bad and stuck shut, the temperature would rise to 210 quickly
enough that I had trouble catching it and backing off on the throttle. I
decided to go 10 degrees lower this time to give myself more reaction time.
I made the change a few years ago after discussion with the local truck
dealer and so far the engine seems happy.

Tom

At 07:51 AM 5/2/2001 -0400, Robert_Schreiber@lotus.com wrote: