Compression is great,l airflow seems good too. It has a keihin pe20 carb on it, way different than my Honda, and it starts intermittently. It seems that when you adjust the idle all the way in it will start, and it runs great. Then when you shut it off and it cools down you are back at square one trying to get it started again. I am kinda lost as to what to do next to make it easy like my Honda. Guess I should stick with Honda.