105488-0574 ZEXEL 9 420 612 590 BOSCH GOVERNOR 9420612590 1054880574 1157703730

Caterpillar: Confidential Yellow
OPTIONAL:IMPROVED FUEL TRANSFER PUMP SEALS FOR COLD WEATHER OPERATION; CHECK FOR NOZZLE GAS LEAKAGE - 3406B IN ALL APP LICATIONS - PI7090 - MAILED US AND CANADA, CACO, COFA, BRAZIL, CFEL, COSA, TRUCK, MARINE & AGRICULTURE TEPS
  The information supplied in this service letter may not be valid after the termination date of this program.   Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.
IMPROVED FUEL TRANSFER PUMP VALVES FOR COLD WEATHER OPERATION; CHECK FOR NOZZLE GAS LEAKAGE, 3406B Truck, Marine, And Industrial Engines; 3406B Generator Sets; 16G Motor Graders; 245 Excavators And Front Shovels; 824C Tractors; 825C, 826C Compactors; 980C Loaders, 1254, 1256, 1250, PI7090 U-56 A-36 AU-47 B-21 C-51 E-34 O-42 TT-3 TA-3 TM-4 optional parts stock action needed If you received the January 6, 1984 Safety Service Letter (PI1019) and/or the December 2, 1983 Service Letter (PI7049), do all three PIP's at the same time. Problems ****Transfer Pump Valves**** The fuel transfer pump on the above engines has three 1W6182 Valve Assemblies. The one valve in the piston can break in extremely cold weather due to excessive restriction from jelled fuel. Some damage can also occur to the other valve assemblies. A new valve with less flow restriction is now used in the piston and at the other two locations in the pump. These valves are directly adaptable to earlier engines. ****Combustion Gas Leakage Around Fuel Nozzles**** There is a possibility that combustion gases can escape by a fuel injection nozzle and into the adapter. The high temperatures soften the end of the nozzle body and cause the tip to come off. The usual cause for escaping combustion gases is either a loose nozzle in the adapter or a cut in the carbon dam (gas seal). See Illustration 1. Nozzle hold down clamps are all now tightened properly, and an improved chamfer is machined inside the bottom of the adapters to prevent cutting the carbon dam. ILLUSTRATION 1 (SEE ILLUSTRATION) Affected Models And Parts Needed Some of the following vehicles contain the 3406 Engine with the former scroll fuel system and are not in this Program. PIN's (Product Identification No.) Or Serial No. Model Both Problems Gas Leakage Only 3406B Truck Engine 7FB1-8348 8349 - 10145 3406B Marine Engine 4TB1-383 384 - 396 3406B Industrial Engine 6TB1-1184 1185 - 1276 3406B Generator Set 2WB1-1044 1045 - 1166 16G Motor Grader 93U2284-93U2417 93U2418-93U2432 245 Excavator 95V1084-95V1111 95V1112-95V1116 245 Excavator