1987/02/16 Caterpillar

Fuel Ratio Control Diaphragms On 3161 Governors{1278}

Usage:

All 3500 Family Of Engines;
D11N, 776B Tractors;
777B, 785, 789 Trucks

Fuel ratio control diaphragms (the lower 2W122 Diaphragm and the upper 2W121 Diaphragm) are serviced. See illustration. They are also part of the 7C4265 and 7C3998 Fuel Ratio Control Groups. The 7C4265 Fuel Ratio Control Group is used on 777B, 785 and 789 Trucks and on D11N and 776B Tractors. The 7C3998 Fuel Ratio Control Group is used on all 3500 Family of marine, industrial and generator set engines.

Location of parts.

When replacing the diaphragms, be sure that a 7C4000 Screw Assembly is installed in the fuel ratio control group. This assembly has a steel screw and an aluminum piston that will improve diaphragm life, especially in high vibration applications. Also, be sure the 5H6005 Seal is installed on the 7C4000 Screw Assembly. This seal, together with the aluminum piston, reduces the sideways motion and fretting of the diaphragm. Always reset the arming pressure and level setting after replacing the diaphragms.

NOTE: A special level setting may be required for satisfactory performance in some high altitude application

Caterpillar Information System:

1987/02/16 Some 2P4005 Oil Filter Assemblies May Be Difficult To Install{1318}

1987/02/16 Change To Interval For Valve Lash Adjustment{1103,1105,1123}

1987/02/16 Check Bolt Tightness Before Replacing Gaskets To Stop Coolant Leakage{1393,1362}

1987/02/16 Incorrect Use Of Fuel Heaters Can Reduce Engine Power{1296}

1987/02/16 Guidebook For Caterpillar Inspection And Maintenance Program For Standby Generator Sets{0354,0370,0372}

1987/02/16 Polarity Connections And Use Of Service Meter Films When Service Meter Kits Are Installed{7480,7000}

1987/02/16 Self-Powered Hour Meters Available{7480,7450}

1987/02/16 12-Volt Starter Solenoid Available For 7T2265 And 7T2266 Starting Motors{1407}

1987/02/16 Resistors Used To Protect Electrical Wiring{1400}

1987/02/16 The Importance Of The Disconnect Switch In Regard To Fire Suppression Systems With Automatic Actuation{7401}

1987/02/16 Use The Correct Vacuum Pump When Servicing Air Conditioning Systems{7320}

1987/02/16 New Penetrating Oil/Lubricant Available (NACD Only){0645,0600}

1987/02/16 Grommets Added To Dampen Vibration{1307}

1987/02/23 Stronger Timing Gear Housing; Additional Stud Used At Top Of Housing{1151,1201}

1987/02/23 Two Front Timing Gear Housings Available{1162,1150}

1987/02/23 Water Temperature Regulators Standardized{1355}

1987/03/02 Bolt-On Roller Groups Available For Competitive Hydraulic Excavators{4150}

1987/03/02 Tools Available To Install Plastic Tie Straps{0709,0738}

1987/03/02 Check For Plugged Orifices In Mechanical Pressure Gauges{7450}

1987/03/02 Water Separator Available{1263}

1987/03/02 New 8T5261 Bushing Installer And Remover Adapter Tool Available{0600}

1987/03/02 New Fan Drives Used{1358}

1987/03/09 Cylinder Head Water Directors No Longer Needed In Direct Injection Engines {1115}

1987/03/09 New Air Cleaner Mounting Brackets Used For Heavy-Duty Air Cleaner Groups {1051}