1986/11/10 Caterpillar

New Fuel Ratio Control Used{1278}

Usage:

3406B Vehicular Engines ( 70V ) Used In 245 Excavators, 824C Tractors, 825C and 826C Compactors, 980C Loaders;
3406B Truck Engines ( 7FB)

Description of Change: A new fuel ratio control is being introduced that is mechanically simpler and less costly than the former control. The control is initially activated following engine start-up by oil pressure acting on the components of a unique lever assembly inside the governor housing. Following activation, the control operates on manifold pressure only.

Unlike the former fuel ratio control, the component parts of the new fuel ratio control are not serviced separately. In the case of a diagnosed diaphragm failure, for example, the control is readily replaced as an assembly.

Testing and adjusting procedures become simpler with the new fuel ratio control. The control linkage is nonadjustable (no "static lever setting"). Ratio control setting checks are performed dynamically. Setting changes are accomplished by loosening a two-bolt retaining plate and rotating the control housing either clockwise (more negative setting) or counterclockwise (more positive setting). Checking for diaphragm leakage or boost pressure that gives full torque rack travel is performed the same as in the former control.

Comparison of fuel ratio controls.

Adaptable To: The new 7W5318 Fuel Ratio Control is initially being introduced on the above vehicular and truck engines (selected arrangements). Information will be forthcoming on adapting the new control to earlier engines.

Caterpillar Information System:

1986/11/10 Caterpillar Antifreeze Now Used And Available From Parts Departments{1350,1395}

1986/11/03 Nylon Seals Used On Lockwire To Seal Critical Areas; All Subsidiary Dealers Can Now Order Parts Service Seals {1257,1264}

1986/11/03 Two New Cold Weather Fuel Heaters Available {1296}

1986/11/03 High Loads Require Additional Oil Capacity {1318,1214,1215}

1986/11/03 New Jacket Water Heaters Have Longer Thermostat Life {1383,1450}

1986/11/03 Custom Product Microfiche Library Is Now Part Of U.S. Product Parts Book Library {0374}

1986/10/27 New Indicator Instrument Group Available To Measure Crankcase Blowby And Radiator Air Velocity{0781,1200,1350}

1986/10/27 Stronger Oil Level Guide Used{1326,1300}

1986/10/27 Check Oil Drain Hole In OR2671 Or OR2621 Remanufactured Cylinder Heads If Head Used With Breather{1100,1300,1317}

1986/10/20 Check Connecting Rods After Engine Failures Involving Hydraulic Lock{1218,1225}

1986/10/20 Caterpillar Crankshaft Heat Code Locations{1202}

1986/10/20 Orifice Screen Assembly Now Used For The Timing Advance Mechanism{1251,1272,1288,1292}

1986/11/10 Adjust Bosch Solenoid If Replaced Or Reinstalled{1407,1453}

1986/11/10 Use Gas Detector Tubes That Have Expired Dates To "Break In" The Combustion Chambers For The Fuel Sulphur Analyzer Group{0651}

1986/11/24 Smaller Diameter Fuel Supply Line May Cause Power Loss{1274,1250}

1986/11/24 Updates To The Parts Book Microfiche{0374}

1986/11/24 Engine Mounts Available To Provide Clearance For Deep Oil Pans{1152,1302}

1986/12/01 Product Support Literature For Military Machines {7567}

1986/12/01 Hour Meters - Mechanical Versus Electronic {7480,7478}

1986/12/01 Use Correct Pistons And Rings For 3406B Truck Engines {1214,1215}

1986/12/01 Improved Retaining Bushing In Fuel Injection Pump {1251,1250}

1986/12/15 How To Use Literature References In Column Three of the NPR (Numerical Parts Record){0374}

1986/12/15 New Track Press Assembly Specifications Decals Available{4150}

1986/12/15 Check For Dirt Before Replacing Pyrometer Switch{1050,7466}