The manual for my model 660 said to put the deck in the low cutting position, take the disengagement rod out by pulling the cotter pin and taking the washer off and setting the rod in or out In is supposed to loosen and out is supposed to tighter or vice versa. Cannot recall. But you adjust this until the deck moves forward and back with losse tension in the belt when in stop/disengage. Maybe I turned it to tighten or loosen?Hope this helps.
lumper20, June 2007
