Chainsaw Repair

Had the same problem on that early Echo 600 I put together, solved that leak with an O ring because it has a round flange on the filter.  Maybe you can work up something similar to keep it from drawing maverick air at that gap.  Otherwise a dab of grease should help. 

Just thought of something else, maybe a dab of that liquid plastic would build up that surface enough to seal?  My Son fixed the tilt cap door gasket on my truck cap with this stuff and its held up for years.
http://www.lowes.com/pd_23467-138-31018L_0__?productId=4750803&Ntt=pvc+plastic+cement&pl=1&currentURL=%3FNtt%3Dpvc%2Bplastic%2Bcement&facetInfo=