CRANKSHAFT GP 1456688 - Caterpillar

Industrial, Marine And Generator Set EnginesDescription of Change: On 3208 Engines, it is possible for the fuel transfer pump to have enough suction pressure to suck air past the seal around the governor main shaft. To prevent this, a check valve has been added to the governor housing at the housing cavity for the shaft seal and bearing. See illustration. The check valve limits the pump suction pressure inside the cavity and prevents entry of air by the shaft seal. This minimizes the possibility of low power and hard starting.
Adaptable To: The 9Y4966 Valve Assembly is effective with the following 3208 Engines: Industrial Engines-90N70907, 3Z7742Marine Engines-75V9816, 1Z15404Generator Sets-29A2103, 30A3418The valve can be installed in the governor housing on earlier engines by reaming out the existing hole near the main shaft seal as shown. The valve is preset to open at the proper suction pressure and this setting should not be changed.
Location of check valve added to the governor housing.