The knotter on a Massey Ferguson baler is what ties the twine. This component can be adjusted by changing the density of the bale, which affects its weight. The knotter has rotating discs that make loops out of the ends of the twine, and a needle on the baler wraps the twine around the bale. The needle brings the twine back through the loop made by the knotter, and tension is generated to tie the twine into a knot. Knotters can be adjusted one of two ways: automatically or manually.

Turn the Massey Ferguson baler's pressure gauge valve on the automatic density adjuster to the desired density. Adjust the gauge pressure by turning the valve clockwise or counterclockwise. Turning the valve clockwise reduces the flow of hydraulic fluid to the baling compartment, loosening the knotter and increasing the size of the bale. Conversely, turning the valve counterclockwise increases the flow of hydraulic fluid to the baling compartment, tightening the knotter and decreasing the size of the bale.

Turn the knobs on a manually controlled knotter with your hands, to make similar adjustments as in Step 1. Use vice-grip lock pliers to turn these adjustment knobs, if the controls stick and cannot be turned easily by hand. You'll need to turn two knobs on a Massey Ferguson square baler and four to six knobs on a round baler. Each knotter has its own adjustment knobs, so you must turn each knob an equal amount to correctly adjust all the knotters.

Pull the pin on the older Massey Ferguson balers to adjust the size of the bale and tell the knotter when to tie a knot. Push the pin back into one of the holes on the bale size indicator cable to make the knotter adjustment. Move the pin closer to the bale size indicator cable spring to make the bales larger. Or move the pin away from the spring to make the bales smaller.