I know this question has come up in years past but I'll ask it again.

My diesel (Volvo MD2B) now has about 200 hrs and I changed the oil at 50
hrs. I changed it again yesterday, just because it had been over a year
since the last oil change.

Beyond the 50 hr break-in oil change recommendation, I find no further
guidance in the owners manual.

What is the normal change frequency for a sail boat aux. engine when it is
in frequent use. (cruising with daily operation)??

FWIW. I'm using Shell Rotella-T 15w40 and change the filter each time.

Thanks,

Steve
s/v Good Intentions