Motor oil

[Cat Nap3]

25hp Honda out board it’s about 10+ yrs old and in good shape.
It’s on a sailboat so it doesn’t get much use. Mostly 1/2hr runs.
I have always used regular oil with no problems. Changed yearly.
The question is would there be any advantage to using synthetic oil ??
I plan to keep the motor for a long time with same operating as conditions.
Any opinions ??
Thanks. Nick

[Compass790]

Does the engine have an oil filter? Sorry if this is a dumb question but I'm not used to any outboard bigger than 15hp or four stroke outboards.
I prefer synthetic in my car as you can run much longer between changes & its fractionally better gas mileage. Also good overheating protection.Not sure if I would bother if engine had no oil filter tho synthetic seems to stay much cleaner.
If you are going to change it annually anyway possibly not much advantage

[tkeithlu]

Motor oil has gotten so good that I think we're going to run out of "S" codes. I can't really see an advantage under your conditions. What's really important is that you are changing it each season.