How to change the zigzag cam for 9518-30 spinnaker sewing machine

Sailmaster 9518-30 (www.cowboysew.com/product5.htm) is the long arm medium weight zigzag sewing machine for medium weight material. 

It sews spinnaker better than any other machine built today. 

This machine standard supplied with 4 cams for straight stitch, 1-step zigzag, 2-step zigzag and 3-step zigzag (triple zigzag). During the production, you need to change cams according to different seam requirements. Instructions:I. Change zigzag cam 
1.Loosen the hex nut (01), take off the cam(03); 
2.Loosen the screw (30), take off the cover (29); 
3.Mount the right cam onto the shaft(05) Caution!! The hole on cam must be directed at the dowel pin on the shaft, then light turn the crank (21), make the pin roller (19) on shaft fit to the groove on cam. Mount the wash and hex nut and tighten, then turn the flywheel, the machine should run smoothly. 
4.Mount the cover (29) and tighten the screw.

II. Needle timing adjusting Different cam will cause change of timing, please adjust needle timing as following steps: 
1. Loosen the screw on top of machine, and take offer top cover. 
2. Loosen 4 endless screws(15), turn the upper shaft a bit and then tight 1 of 4 screws (15), turn the flywheel lightly and watch the needle movement, the correct position is: WHEN NEEDLE TIP MOVE TO 8MM ABOVE THE NEEDLE PLATE, THE NEEDLE STOPS SWAY. 
3. After finish the adjustment, tighten 4 endless screws (15). Caution! The end face of screw must against the end face of bead flange (12). 
4. Mount the top cover and tighten screw. 
 III. Adjust the gap of worm gear After run for certain time, the gap of worm gear will be appeared, please adjust the gap as flowing steps: 
 1. Loosen the screw on top of machine, and take offer top cover. 
2. Loosen the screw (15) on bead flange (14), move bead flange towards the left; 
3.Loosen 4 endless screws(15)，slowly move worm gear (16) towards the left, to minimum the gap of worm gear, then tighten screws (15), lightly turn the flywheel, the machine should run smoothly. 
4. Move bead flange towards the right and against worn gear. 
5. Mount the top cover and tighten screw.