Just my thoughts on fuel
I run Omega 15% unlessif it's a large 2 stroke I drop it to 5%.. A lot of your china 4 strokes run a steel liner and a iron ring. The castor actually glazes this surface over with a hard, very slick film, that these type of porous metals benefit from. It also works well in the higher end engines also, so to keepthings simple I just buy 15% Omega in most everything. The down side is the castor bakes on the engine overtime.
The only down side to straight syn, is it,s lower flash point which is not a problem for many that use it. I have no problem using CoolPower, just prefer to stay with what I always use.. As others have suggested they add a little oil, or castor, just for added insurance.