At TDRC we have been running gas engines for a while and this is the best oil we have used yet period.. Annual tear-down inspections show very little carbon build-up and well lubricated parts.I personally use this in all of my 50cc-170cc and even my rotax 52HP UL engine!!! Stihl Ultra HP is a synthetic blend oil that burns cleaner than the other brands and is more affordable! Each bottle mix's 2.5 Gallons @ 50:1. For best results use a ratio cup
STIHL HP Ultra 2-Cycle Engine Oil
HP Ultra is a fully synthetic 2-cycle engine oil specially suited for high performance Chain saws,Trimmers and power tools. This oil has outstanding engine cleaning characteristics, plus “ultra” superior lubricating qualities in comparison to other 2-cycle engine oils. It is ideal for use in STIHL 4-MIX® engines. This oil is biodegradable, degrading by 80% in 21 days.
STIHL HP Ultra combines excellent lubrication with an exceedingly low tendency to carbonize. Result: excellent lubrication, excellent cleanliness and excellent protection for your high-performance engine, especially in continuous duty and at full load.