When I had my 4 stroke, before it got stolen, I always used Chevron oil. Oils made in Texas are good. I always stay away from Pennsylvanian oils (Quaker State, Penzoil) they have a higher than normal ash content. Gums up your motors prematurely, car and boat.

If you are going to go with a synthetic Mobil 1 is top choice.

Which ever type of oil you use you will want to be consistent. Don't switch between normal oil and synthetics. You will develope oil leaks.

My $0.02 worth.
_________________________
Carl C.