Need to know how to adjust a clutch on a Snapper riding mower?

I have a Snapper riding lawn mower.Model #300922B Part #84699.The clutch needs to be adjusted it wont move forward in any gear higher than 2nd and reverse is fine.I have downloaded the manual and it says there is an adjustment but does not outline how th make the adjustment and the dealer is of no help.Thank you in advance.Need to know how to adjust a clutch on a Snapper riding mower?Try Snapper customer service. I would think their number is in the manual you have@