"Chunky" wrote in message
u...
My 1995 Mercury 135HP 2 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.




Assuming that the thermostats are operational and the pressure relief valve
on the side is not sticking, then you may need the heavy duty impeller that
Merc sells, but it is not the one included in their water pump kits. The
following is an excerpt from a friend who "chased" a similar problem on his
V6 Merc for quite a while.

"As for my intermittent overheating problem, we finally cured it -- but I
had
to call an engineer at Mercury for the magic bullet. It was my starboard
engine that was overheating at displacement speeds
(approx. 1200-1800 rpm),

The Merc guy said to substitute what he called the "standard" nylon-hub
water pump impeller (Merc #47-89984T-3) that came with the rebuild kit
(#46-96148A) with the "heavy duty" brass-hub impeller (#47-89984T-4). It's
the same impeller, just different hub materials. He couldn't explain why,
but said it usually works with problems like I was having. Son of a gun, he
was right. I switched them out and the problem is gone. Hallelujah."

Hope that this could be of help to you.

Bill Grannis
service manager