My 48 inch walk behind mower, less than 2 yrs old is boggin down when the blades are engaged.?
I just recently had the blades sharpended, its not cutting irregular, it's just seems like it doesn't have enough power. This commercial mower has had very little use, only my 1 acre lot.
It doesn't appear to have a lack of power when the blades are not engaged.
Any suggestions?

Check for worn bearings. I just went through the same thing and upon a good inspection, found one deck bearing that was "toast".
Do you engage blades out of the grass, like on cement pad or drive way ? If so and you still have problem of bogging down, then look for a restriction around the blades like clippings and dirt build up. Find out why the blades wont turn freely. Were the blades reinstalled correctly so the turn freely ? Good Luck