[mehrkam]

Besides the fact the a 16:2 P60 gear box is not really good for lift applications, with bag & tag / shipment on Tuesday, here are some options.

If you don't have a higher gear ratio P60, then you need to increase the overall gear ratio. Reduce the sprocket size on the motor and increase the other.

I have assemble and disamebled thes P60s numerous times and found that ever now and then the smaller ones tend to bind up easily when tightening the screws. Make sure that the motor mount and shaft plates stay flat. Tigheten as though you were doing your car wheels in a cross pattern. Don't tighten up in CW or CCW pattern like some do. That will bind up the gear box and prevent it from turning.

Hope this helps.

Good luck