There is no drop in actual RPM. Any drop that brief and sudden would be
detectable in the sound of the engine, especially on soft mounts with all
that rotating inertia. I've listened carefully when this is happening and
there is *absolutely* nothing detectable in the engine sound or feeling
through my feet.

This is also a change in behavior. It didn't do it the last two seasons or
early this year.

--
Roger Long

* Roger Long wrote, On 7/5/2007 9:31 AM:
There is no drop in actual RPM. Any drop that brief and sudden would be
detectable in the sound of the engine, especially on soft mounts with
all that rotating inertia. I've listened carefully when this is
happening and there is *absolutely* nothing detectable in the engine
sound or feeling through my feet.

This is also a change in behavior. It didn't do it the last two seasons
or early this year.

Are you sure then that your tach is reading the flywheel? My Yanmar
does that and the tach is pretty steady, even when there are serious
charging "events" going on. Yesterday my belt was getting cooked so
it slipped badly - the Amps were all over the place but the rpm was
still rock steady. Its possible someone replaced the tack with an
alternator sensing type, which of course can lead to all sorts of
curiosities.