8v71

Im currently running a 8v71 in my boat that was revently aqquired.
What is a good operating temp for this engine and what is to hot for it

The book I have says 160°-185°. My DDs run about 175° at 1800rpm.

On DD 671TIB's I run 160-170. I have a guess at what is too hot but there are folks here WAY more qualified then me to answer that.

The above suggestions are ok. 180 f. Thermostats are common for these engines but 160f and 170f as well as 190f stats are available too.

What you need to understand is that the temperature stamped on the stat is the temperature that the stat BEGINS to open. Then, as fuel is added to compensate for load the stat will be FULLY open at temperatures ranging from 185 for a 160f stat up to 197f for a properly operating 180f stat.

So, in a nutshell, "normal" can be from 160 to about 200f. "depending".

These engines should have an overtemp warning system that will alarm at 210 to 215f for safe operation.