There was a discussion about something similar (though not exactly the
same)
in Practical Boat Owner no 446 February this year in "Ask The Experts" on
page 69. I don't entirely understand your problem and I similarly don't
entirely understand the article but there are enough points of similarity
to
lead me to point to it. The heading was "Yanmar engine revs"

Hoges in WA
Remove the zeds.

Thanks Hoges but I can't seem to access the Ask the experts column online
from PBO's website. I will try and find that copy next time I am in the
library.



regards


Steve Hopkinson