what is everyone's opinion -what would be the major cause of ventilation-(most frequent)

-The reason why I am asking is that I recently heard from my shop that the problem i was having on my motor is a ventilation issue/set up. Since i have some down time I pulled the prop off and plan to get it blueprinted or recondiioned.
I called skeeter and check where the settings on the jp should be and they match up. The only thing left is the prop(which does have some dings on it) no bad though.