Originally Posted by lostinbaja

My Brother had the same problem. If the pinion was properly lined up with the spur, the grub screw on the pinion would not tighten on the flat area of the motor shaft. Naturally he didn't want to buy another motor with a longer flat machined on the shaft or locate another pinion with a different offset that might work. He brought the motor to work and machined the flat on the shaft long enough to allow the pinion grub screw to tighten on the flat.