The mower started throwing the drive belt off every time I let out the clutch. Diagnosis revealed that the shoulder bolt that the clutch idler bracket pivoted on was stripped. No replacement could be found anywhere. Not happy with the design of the bolt, I decided that a regular 3/8-16 bolt could work if it had a shouldered washer on it. I decided to make the flange portion bigger than the flange on the bolt. That will better support the idler bracket. After an hour of mowing, it seems to be working fine.