Industrial sewing machines, like the Consew 225, can make 3,500 stitches per minute after the break-in period. If the timing goes out, the Consew will make irregular, loose stitches. Improper timing can also damage the needle and the machine. Broken metal shards can even shoot back toward the sewing machine operator.
Use your hand to slowly turn the balance wheel counter-clockwise. Watch the walking presser foot as the outer sections step back and forth around the vibrating center presser foot with the needle hole.
Pay the most attention to the position of the vibrating foot when the needle pierces it and lifts back out. If the needle is going into the hole before the vibrating presser foot is fully down, your timing is too slow. If the vibrating foot is lifting up before the needle has pierced it, your timing is too fast. The foot should go all the way down, the needle should enter and leave, and then lift back up.
Look at the back of the sewing machine. Follow the lines of the sewing machine body, beginning at the needle, going up and to the left. Six and a half inches from the end is a large, black wing nut. A hole about two inches long and one and a half inches wide is directly behind the wing nut in the body of the machine.
There are two screws on a round metal cam about 1/2-inch thick. Release the cam screws by turning the screwdriver counter-clockwise, but do not remove the screws completely.
Turn the cam forward about 1/4 inch to increase the timing speed or backward 1/4 inch to reduce the speed. Tighten the screws with the screwdriver.
Test your adjusted timing to make sure it is correct by hand-turning the balance wheel and watching as the needle pierces the walking foot again.