Dial 4-1/8 in. H X 4 in. W Gray Cast Iron Variable Motor Pulley

Variable pulleys must be opened 2½ to 5 turns, depending on air resistance or motor will overheat. If motor cycles (starts and stops due to overheating), open variable pulley until the motor stops cycling. If cycling persists when pulley is fully opened, you must use the next size smaller pulley. Always use pulley size recommended by cooler manufacturer.