Here's another question for the expert mechanics.......in all my years of going thru an engine, I've never heard of "air leaks" being a problem. Apparently, chainsaws can develop leaks at the crank seals, with regular occurrence.....is this some sort of odd-ball problem, re-call issue, etc.........OR is it a very common problem? I've done leak-down tests on drag race engines...........yet never imagine a little 2-stoke engine could also develop such an issue. Search eBay for chainsaw air leak.....there's dozens of them!