On Thu, 12 Oct 2017 10:52:37 -0400, "Mr. Luddite"
wrote:

THere's something about gas engines running for hours at 3,600 to 4,000
RPM that disturbs me, even though I realize they have cams, etc., that
are designed for it. Seem to remember the general rule was 1,000 to
1,500 hours before a rebuild.

That must have been a "rule" made when engines were still "detroit
iron". Once the Japs showed us you can make a better engine, all of
them will run many thousands of hours.
My Yamamerc 60 had over 3000 on it with no indication it was in need
of anything. I got rid of it because of all of the other $200-500
screw on parts that were nearing end of life.