We have a Volvo
MD2040 (yeah, we're sorry too) which has developed a new quirk - when charging
the batteries (that is, not under load or in gear) after about an hour the engine
revs suddenly shoot up of their own accord. As soon as you throttle back to neutral then re-increase the revs it is OK (for another half hour or so). It goes OK when running under load.
Initially it happened while we were at sea, and we suspected (after reading Nigel Calder) it was an over-filled oil
issue, with drops being sent into the engine
in a rough sea, but now it is doing it in flat calm anchorages
We are currently in Nosy Be, Madagascar
, and English-speaking mechanics are thin on the ground, so any advice would be appreciated.