I have an Echo PB-250 LN leaf blower that died on me the other day. Have had it for two years and haven't used it a ton. The power has slowly decreased over the last year or so. In the spring I changed out the plug and it ran better for a little bit and then lost power again. Yesterday I fired it up and it ran poorly, bogging down and then finally quit...won't start back up. I use no ethanol gas for mix and always drain it when I am done. Pulled the plug and muffler and the piston and cylider walls are black with oil. No scoring that I can see but it is pretty hard to tell with the oil in there. Seems to have good compression. The last plug I replaced and this one look pretty dark but I guess I dont know exactly how it should look. I probably mix at closer to 40:1 than the 50:1 recommended so maybe that is the issue? Wondering what the problem might be and what to do about the oil in the cylinder? Thanks for any help