I have a AYP 42117 that I'm having trouble with the main drive belt slipping off the pullies. I've replaced the belt but that doesn't seem to help and their seem to be no adjustment to take up any excess slack. Manual has been difficult to find. A Huski LTH18542A seems to be a similar mower but that manual shows that their's no adjustment. No visible sign of damage and mower worked all season without incident.