Posted by ajlorman (ajlorman@…>)
Many thanks to all who provided advice in response to my inquiry
concerning wavering rpms. Since I didn’t think it was a case of
clogged filters, I thought I’d try reducing the load on the fuel pump
by bypassing the original Fram filter and plumbing the fuel tank
directly to the newer Racor. This weekend, I did so (I also changed
the filter just to be sure). I then took Ab Initio out for an hour
cruise under power and I’m pleased to report that the tach did not
budge from where I set it. Also ran the engine yesterday for an hour
before and after sailing with the same result. My unscientific
conclusion is that sometimes too much of a good thing – in this case,
filtration – is just too much.
Al Lorman
F30 Ab Initio
— In freedomyachts2003@yahoogroups.com, “ajlorman” <ajlorman@…> wrote:
My otherwise quite reliable Yanmar 2GM20F began to behave a bit oddly
on my recent cruise. Sometimes, not always, I would set the rpm for
2800 and after holding that for a while it would slow down to 2500.
Sometimes it would rev up again on its own; sometimes not. Once this
pattern started, it seemed to continue, though the periods of up and
down varied in lenght. The rpms during this behavior generally ranged
betweem 2500 and 3000. I assume, perhaps incorrectly, that if it were
a fuel problem, it would go down and stay down, or even die.Any suggestions before I call in a pro?
Many thanks.
Al Lorman
F30 Ab Initio