I have a Yard King riding mower Model 465615x99A with a 18HP Kohler engine and a Peerless VST205 trans axle. It seems to pull okay in reverse but doesn't go anywhere when I attempt to climb any angle of grade. I have tried to adjust the "clutch" on this mower by following the instructions in the owners manual but find that the directions are poorly lacking as is the engineering of the adjustment components. Do anyone know of a simple, effective method of adjusting the "clutch" or any other information as to what the problem could be with this mower? By the way, the drive belt is not slipping.

The clutch is actually a pulley mounted on a spring loaded swing arm. When you push in the clutch the pulley moves and no longer has tension againist the pulley. Get your head under the deck and have someone actuate your clucth, you'll see the pulley and belt interact. The rod that moves the pulley has an adjustment nut on the rod, you need to make the rod a bit shorter, sometimes you must disconnect the rod and rotate the rod to screw deeper into the nut.

Ballengerb is correct, you adjust the clutch as he stated.

I started buy ordering and installing a new belt. It was the correct belt but seemed to be to long. I adjusted the "clutch" as much as possible and although the mower now moves very well I believe that I'm in for a pulley change out.
Thanks for your advice.