The temp guage goes way up into red. No alarm yet, I usually alter speed
before it gets too hot.

The funny thing is the range that it heats up on.

Just above idle its fine. A little faster and it heats up quick, then after
that if you get the speed up it cools off to normal. Thinking about it, what
could be happening is that at higher speed the ram effect is forcing water
thru the cooling system. Slow down and it relies on the pump which is not
performing optimally.

Regards,

"Boatriggr" wrote in message
...
StrokeOutboard has decided to overheat whenever the
RPMS are around 1200-2000. Either side it cools off but in this range it
warms up fast. The water pump is working because it streams water ok.
Nothing seems to be bloking the intake.

When you say overheating, do you mean the audible alarm comes on? Do you
have a
guage that reads hot?
Does it have a water pressure guage? if so what is the pressure at this
rpm?
The impellor should be changed yearly, so that a logical place to start.

More questions. What hull is the motor on?
I assume your hull is "mushing' at that speed. Not on plane, just moving a
lot
of water.
Some boats were known to get hot running at those rpm's. The hull diverts
the
water creating an air pocket allowing temps to rise.
You might try changing the trim angle and see what happens.

BR