Ok..I got my exmark lazer about 3.5 years ago and have put 1700 hours on it. It is running weak (blades don't seem to be spinning as fast as they should... cut looks a little rough.. and I put brand new blades on every other week.).. has been for almost a year now but it's really showing now that the grass is growing like crazy. I have kept poor maintenience... not enough oil changes and was wondering if this was the sole cause. I have noticed it doesn't appear to be running at full throttle and when I push the throttle level on the engine it runs a little harder so I'm going to make that adjustment to make sure I'm opening it all the way up. Are there any other minor adjustments like that.. that could possible get this thing cutting good again? Just wanna make sure it's not something simple before I think about gettin a new engine or mower.. which brings up another question. If I were to buy a new engine for the mower.. do you think it would run like new.. like get as many rpms on the blades. Or would it be a tad weak due to possible wear on spindles and so forth. Just don't want to buy a new engine then still be dissapointed in performance.