Frequency of Changing Oil & Fuel Filters
I have a Yanmar 1 gm. I changed the oil and the oil and fuel filters before the start of the season, and put maybe 20 hours on the engine this season (really only motor on and off the mooring).
Should I go ahead and do this maintenance again? The manual suggests oil change every 100 hours and oil/fuel filter every 250 hours, so it does not seem necessary, but I'm unsure if there's a reason to do this at a minimum annually regardless of hours.