hi
flying OS two cycle glo engines for 20 years about when the FS series of engines came outthe FS series and the FSR series ( earlier than the FS series ) of engines have always performed outstanding for me( powerful - reliable cannot wear them out ) as did the earlier FP series (aluminum color )
had problems running my 91 FX engine until OS made replacement parts to remove the needle valve from the back plate -as heat transfer was causing air bubbles in the fuel line from the remote needle valve assembly to the carb took me to long to correct the problembut my engine was not damaged as some required new bearings and ring from OS due to air in fuel lines causing high heat problems and metal damage
i have a 75 AX that is a powerhouse and turns an inch more prop than my 91 FXthe power the AX series and size props they turn for there size engine just surprises me all the time they are the most powerful OS engines ever made IMOmore money but worth it
i love my OS 46 FX my Evolution 46 glo my evolution 52 heli engine and my ST 51all the above are super strong runners for 40 size airframes
i am very sure that my outstanding success with all my two cycle glo engines (only style engine i chose to fly ) is totally due to the glo fuel i usewhich is MORGAN OMEGAcastor and syn mix15%- for 18 of my 20 years in the hobby (do see my quote at the bottom of my post )
the first two years i flew i used MORGAN COOL ( crule ) POWERand i suffered all kinds of engine wearrings -bearings etci do all my own engine repair work-i would never use a full syn fuel for any reason after that experience ( just clean the plane off )
i truly cannot remember the last time i needed to replace a set of bearingsi do change a ring from time to time if compression falls offa new ring brings the compression back as if the engine was new again
my engines run and stay newbreak in procedure has a bit to do with my results
that is my own experience with OSand it is generally great
BEST REGARDS TONY