Over-revving of throttle on 1998 38 Ocean

[Jeffatoms]

We have experienced random revving of the engine on the last three outing.  The first time we thought it was cavatating because it happened in big swells.  The RPMs jumped about  400rpm for a few seconds and came back down .  The next week it did the same in flat calm but again settled back to the original RPMs after 2 seconds of revving.  Yesterday we were on full auto pilot running in flat calm at 2100 and it jumped to 2500 and stayed for about 4 seconds so I reached up and eased the throttle back to 2200 where it remained for the next 45 minutes until we throttled back down and set anchor using fwd and reverse just fine.

Last year the transmission cable snapped off at one end while we were having a new saildrive installed.  No harm;we
just replaced it. I'm thinking it is a cable end here (23 years old) about to give up the ghost.  I'll endoscope both ends later today.  Other ideas?

Maybe a bit of preventative maintenance is in order.  Does anyone know the cable type and length for a 1998 Bavaria 38 Ocean?

[symphony2]

Morse 33C (The generic type but more than one supplier) and the length will be printed on the cable sleeve somewhere on its run.

[Clivert]

Check your water separater for excess water in your fuel.
This can cause surging

[Jeffatoms]

Thank you for your thoughts!

We have a weird diesel leak too.  It leaks about a teaspoon a week while at the dock.  It appears to leak down on the block somewhere, drips onto the saildrive gaskets, and works it s way to the stern where it eventually drips town to the back side of the saildrive where it accumulates onto a paper towel.  We have paid real engine people to trace it to no avail. "Sorry, that will be $200".  Leter we bought an endoscope but still unable to trace back.