Amsoil exclusively. Go to amsoil website and check out their tests (done by and independent lab). They can also do an oil analysis that will give you a heads up of any engine problems before they become critical. Have been running amsoil in everything I own for 3 or 4 years. Not expensive at all if you use the extended drain intervals. They have oil and filters for everything you own. I became a believer when a guy introduced it to me to run in my jet ski. 2-stroke engines are very prone to engine damage from cheap oil. I disabled the oil injection so I could pre-mix my oil and run it much leaner, which made better throttle response and higher revs. In small two strokes they recommend 100:1 mix ratio. I have run that for three years in my string trimmer and my chain saw. Try that with any other oil!
