I've had the same problem with my 562xp. When I pull the filter off, there is a fine layer of crud lining the inside of the filter holder. Husky offers 3 different filters for this saw, the white felt one that comes with a new saw, and an optional 40 micron nylon mesh filter and an 80 micron mesh filter. I bought the 80 micron filter to see if this would stop the fines from getting into the filter holder, but it didn't help. Seems the problem is the junction between filter and filter holder. Does this o-ring trick keep the filter holder completely clean? Did you grease the oring or leave it dry? Could you advise on the thickness of the oring you used? Looks like it would have to be a pretty small diameter to fit up into the slot on the filter. Anybody lightly oil the white felt filter? a little hesitant to try that, afraid the damp filter would really attract dirt/sawdust/etc and make the saw try to pull air even harder through the filter/holder junction. thanks