Jeff,

The question you ask is simply to vague to provide a spacific answer.

The considerations come from:
Number of cold starts
Number of thermal cycles
Hours of operation at rated output
Hours of operation at idle only load
Hours of operation at less than rated output

In roughly that order.

A cold start is any time the engine gets cranked to fire. This
contaminates the oil and is the time of worst lubrication.
A thermal cycle is any time that the engine is run long enough to get to
operating temperature. This means that all those part have to push on
each other and side and move and it is how things leak or crack.
Hours of operation at rated load actually cause little damage, but it
should be the most common operating condition. This is when/where
piston rings and valve seats wear.
Hours of idle only load beat the bejesus out of the valve gear, and the
rings and pistons don't really fit because that only happens at rated
load.
Hours of operation at less than rated load, but enough to achieve proper
operating temperature will do the least harm. The question would be why
you are not using the engine as designed? Reserve power is nice, but it
is expensive as a first cost consideration (why most sailboat have just
enough power).

I hope this either gave you an answer that you understand or enough
information to phase another question. In the case of the later, I'm
here a lot - try again.

Matt Colie
See prior sig this date


Tamaroak wrote:

So which is easier on my engine, short period at high speed and load, or
long period at low load and speed?

Capt. jeff