I just bought an '04 Exmark Metro 48" walk behind with 50 hrs. It was in real nice condition and runs great. Problem is, I just mowed with it, sharp blades/balanced and the thing clogged starting from the get-go when mowing about 5 inch grass to 3. It was clean underneath when I started and didn't blow anything out, it just collected everything. Anybody else have this problem or know what to do to remedy.