So, I changed the carb on the MS 170, and expanded the muffler opening a bit. Now, I can't get the saw started. I tried giving the saw sniffs of carb cleaner to get it going. However, it wouldn't even stutter. I have spark, the air filter is new. I cleaned the case all up. fuel lines seem to be ok. So, I put a compression tester on it, and I couldn't get more than 85-90 psi out of it. And I heard hissing sounds from around the cylinder somewhere. Any ideas where to start, or should I go get a used Husky 340, or stihl ms260?