Bought this mower off Ebay about a month ago. I have high lift blades on it now, the problem is that its leaving a strip of uncut grass down the center where the blades meet. Ive already had a complaint, so I need some ideas fast. Is 3,340 rpms right, this 14 kawasaki seems to bog down easier than my 32" scag 12.5 kawasaki. Thanks.