Question on API Oil Grades for LA120

[rmatrisciano]

My LA120 manual says I can use API SG. Must be an old rating since I can't find anywhere. Can I use API SM? I was once told any new grade would work for all previous grades, however, that was for a car engine.

 

[Markcuda]

OK, heres the deal, go to your favorite shopping place, locate the oil department, and get a name brand 10-30 oil.
If you are in a climate where you will see 100 degrease on a regular basis, get 10-40.