AA130FIREMAN wrote:I never read what the manufacture wants, I have run everything at 32:1 since I was 12 witha honda 250r, lawnboys, chainsaws,leaf blowers and don't have any problems. The leaner mix I believe today is to satisfy the epa, stihl has started to make a 4 mix engine, 4 cycle that takes mix to help with emmisions. The epa is killing off the 2 cycle, no more 2 cycle lawnboys, dirtbikes , etc. I was never a fan of the idea of amsoil at 100:1, but to each his own, I'd rather burn oil and save the rings.
I bought a Stihl FS-90R trimmer to replace the FS-36 that I'd had for a dozen years. The FS-36 still ran great, but one day I was trying to finish trimming and the head kept jamming up and wouldn't feed. I got so irritated with it I just bent the thing in half and stuffed it in the garbage can.
It wasn't much of a loss since it really wasn't a Stihl but a Ryobi 31cc engine wrapped up in Stihl clothes.
Anyway, the FS-90 is a [url]serious[/url] trimmer and has that "4-mix" engine. It's very torquey and sounds a bit like a 2-stroke that is running too rich and "4-stroking". They recommend using the Stihl oil in the silver bottle, which I believe is a synthetic and is supposed to minimize carbon buildup on the valves. It's 50:1 and I can't see any visible smoke, but it does smell funny. I still run my Lawn-Boy at 32:1 with the Lawn-Boy oil to get my weekly whiff of nostalgia.