Westerbeke Generator oil

[Teamharley]

I have a Westerbeke 4.5 KW gasoline generator in my Maxum 2700 SCR. It is docked in Kentucky. I am changing the motor oil. The manual says I can use either 10w-30 or a straight 30W. Any recommendations? Multi or straight? Brand of oil? Mercruiser oil?

[mmwjr]

Besides the weight what other specifications are in the manual? Synthetic, deterigant rating,...

I would follow all the requirements.

[dronthelake]

I have 1800 hours on a 1998 7.2 and have used Mobile 1 sine 200 hours and still runs like new.

[Teamharley]

It didn't say anything about using synthetic. Calls for API "SJ"

[dronthelake]

"SJ" is an old API classification that was last used in 2001. The current "SM" came out in 2010 and has all the qualities of the previous classification plus recent improvements.

SJ is the next one to be obsolete as did SH, SG and all the way back to the original SA for the cars from the early 1900's.

[Teamharley]

Thanks, I will look for the "SM" rating. Synthetic or detergent?