Marc Auslander wrote in message ...
I'm pretty sure the prop is NOT the problem. I've looked at it in the
water, and its clean. And its the same prop that got to full speed
last year. Should have put that on my initial list - sorry and thanks
for the reminder.
--

Loss of RPM could be an indicating problem caused by oil on the fly
wheel and tach transducer.
With the engine warm and transmission in nutral advance the throuttle
to full RPM 3400. If the engine does not reach the governed setting
the problem is in the indicating system and not the engine.
If the problem is the engine check the exhaust elbo for reduction in
opening. To check elbo remove large hose from elbo and slide two
fingers up inside. If two fingers won't fit through at the top replace
the elbo.

From the author of books on boat refrigeration
http://www.kollmann-marine.com