Thanks to everyone that donated some input ... well, as the saying goes, "a blind squirrel finds a nut every now and then". Checked the air filters today and the inner filter was almost completely covered in black soot ... removed it, reinstalled outer filter and machine runs perfectly, turned it off immediately ... as typical, the easiest thing to check, I checked last and it was the fix. To be honest, I didn't think it could be the filters because they had been replaced less than 100 hours ago. But here's the culprit (I think), I had to install a new exhaust pipe from exhaust manifold over to muffler about same time new filters were installed... of course the new pipe did not fit as snuggly with the muffler as it should have which resulted in a small (may not so small) exhaust leak right above the breather ... I'm assuming the leaking exhaust was being sucked directly into the breather. At least I know now the inner filter will trap those small particles. Getting a new filter and will do my best to makes sure the exhaust leak is fixed ... I feel relatively lucky, maybe the cheapest fix I've ever had on this particular machine, Thanks again to all.