2lumbarleft
ArboristSite Operative
Gentlemen, I have a fair amount of experience tuning various chainsaw makes and models, but I don't do much work on Stihl chainsaws. I have recently received an older Stihl 025 that was rebuilt by a self reputed chainsaw expert. He had installed a new piston, rings, carburetor, fuel lines - the works. When I received it, it was running terrible. I started basic trouble shooting. Spark plug was pig rich. I checked the initial carburetor settings and they were way off - ultra rich. I started at the normal beginning settings, 1 turn out on the low speed jet and 3/4 turns out on the high speed jet. I cranked up the throttle screw and went for restart. The saw came to life and was running better, but I noticed the jet adjustments were very sensitive. I used the official Stihl method of setting the carburetor. I set the high speed rpm to 12,500. Here is where I departed the official tuning method. I have the low speed jet so lean that 1/8 of a turn clockwise will kill the saw, yet there is plenty of fuel for snappy transition 1/8th turn back ccw. The saw definitely will run better if I lean up the high speed jet, but just 1/8 of a turn will jump my rpm to 13,500 which I know can't be good for a class C homeowner saw. I am running 45:1 Amsoil Saber Pro with premium non-ethanol gas. My problem is that I am still blowing snot out of the muffler. I know in my guts that it should be leaner, but I am afraid of the rpm increase. The saw runs good, but should I be concerned about the appearance of too much oil ejection from the muffler? It is always wet and there is a small build up of black oil gas mix below the muffler. Has anybody else experienced this, or is this normal for older Stihl chainsaws? I will say that with 195psi compression this thing has guts, but I have already ripped off the recoil starter handle. Replaced handle and the rope broke one inch down. Replaced the handle and broke the rope 10" down. Installed a new rope and no problems so far, but my rotator cuff is talking to me - ha! Sure would not want to start this saw up in a tree. I am thinking this thing is muffler modded, but I don't want to run this saw at pro saw speeds. The saw was not designed for those kind of stresses. Thoughts?