Hi - I have a Stihl FS-85, 2-stroke-cycle, string trimmer, an echo chainsaw, and other tools with small engines.
The current problem is with the FS-85. It quit, and upon looking into it, I found that the piston was badly scored. So, I bought a piston & cylinder kit, replaced the damaged units, and figured I was home-free. It didn't work out that way. It has good spark, feels like it has compression, and yes I did put gas/oil mix in the tank. It won't even try to start. I even tried ether and got nothing.
Do those symptoms ring any bells to the hordes of users on the forum?
1) was it a genuine Stihl kit or a cheap Chinese "oem copy" .
A lot of the stuff sold on evilbay / craigs list is the stuff that was made by the supplier to Stihl quite truthfully.
However it is the stuff that Stihl rejected as being below production standards.
Next , crankcase prssures are more important than cylinder compression so do a pressure & vacuum test on the crank.
If the crank can not maintian a vacuum then it can not suck the new charge from the carb.
Blue smokes can be a regular bugger to break in rings.
I some times have to run the crank off my drill for quite a while before I get acceptable compression
Remove the pull start & drive the engine off one of the crank shaft nuts, backwards or forewards makes little difference without a plug.
It's running like a champ now. After about a million pulls, I put a few drops of oil in the cylinder, pushed the primer bulb and realized it was sucking as much air as gas, tilted the engine so the fuel pickup was in a deeper spot, pulled once, and off it went. There seems to be a leak in one of the fuel lines, so I am getting new ones. It must have been failing for a while, since now it idles nicely, which it has not done in several years. Whew!
-Ortis
