ORIGINAL: cheechukranch
Tower fuels (Wildcat with the Tower logo on the bottle?) are "at least 18%" oil content. Anyone know the minimum oil requirement for YS and Saito 4-strokes? This seems high compared to other brands so I'll assume it'll work just fine. I've heard that YS deserves nothing less than 20% nitro...is this true?
I can't speak for the Saito line, but YS is 15% min according to the manual for oil content, but I wouldn't chance it with 15%. I would go with no less than 18%. YS are powerhouse engines and the extra lubrication wouldn't hurt. I use YS 20/20 with very good results. I use this on my OS .46FX with a MCP (mousse can pipe). Vertical is unbeliable on a Super Stick with the FX up front spinning a APC 12x4 at 13,980. Back to the YS. I have used Wildcat 15/18 with good results, but the difference is very noticable compared to the YS 20/20. To me atleast. The Saito line probably can get away with using 10% nitro, but I don't believe a YS will like it much. 18% oil is the lowest I would go as far as oil content is concerned on any motor.
YS .91FZ Manual
"Use a good quality fuel which contains 15-20% nitromethane and an oil content of 15-20%. Synthetic or castor oil can be used, or a combination of synthetic and caster. Do no use four cycle fuel due to low oil content."
I never use straight castor oil. It will clog the YS up. Castor is good for break-in purposes, but synthetic is better for the engine once broken-in or a combination of synthetic and castor. A 80% synthetic and 20% castor is good.