Your operator manual will show you how to adjust the clutch. If your clutch throw out will not go over center to lock in the engaged position you may have a lot of dust packed between the clutch disk and the drive plate. If it goes over center but will slip you will have a burning smell. If your clutch still has the cover on it loosen the three bolts a little and look behind it. You will see a ring with a lot of slots in it this is the adjusting ring. On the OD of this ring you will find a retainer that fits in two of those slots. This retainer is held in place by a 1_4" bolt. With the retainer on the bottom loosen the bolt until the ring will turn. Put a punch in any one of the slots and hit it with a hammer counterclockwise to tighten the clutch. If this ring is like most you will have to hit it quite hard to get it to move.