CARTRIDGE AS 7X1121 - Caterpillar

Illustration 1. Location of new parts in fuel ratio control group.Adaptable As: The new parts are direct replacements for the former parts as shown in Chart A. All the parts, except the 2W8449 Strainer, are in effect with the serial numbers shown in Chart B. An in effect serial number for the use of the strainer is not available at this time. It is our recommendation to put an "N" mark on any fuel ratio controls that have had all the new parts installed. This "N" mark will make it easier in the future to tell which fuel ratio controls have the new parts. An "N" mark can also be put on the governor housing when the new strainer is installed. See Illustration 2. Also, when any of the parts in the fuel ratio control are changed, the fuel ratio control must be adjusted according to the procedure in the Service Manual.
Illustration 2. Location of strainer assembly in the governor group.General Information
Springs
To make identification of the springs in the fuel ratio control easier, they have color codes (marks) on them. The springs currently used and their color codes are shown in Chart C. See the Parts Books for the part numbers of the spring used in your application.
Valve Assembly
There has been a problem with burrs on some of the former valve assemblies. These burrs can cause a restriction in the movement of the valve assemblies.
To check the operation of the valve assembly and the internal valve, the internal valve must be moved in the same direction as it moves when installed on the engine, towards the governor. If the operation is checked by movement of the internal valve in the opposite direction, the indication will be that the valve does not operate correctly even if the valve is in good condition. This is because of the sharp edges of the oil groove, not a burr.
Some servicemen have at times ground the ends of the 2P8939 Valve (internal) to try to improve the alignment of the opening in the internal valve with the holes in the valve assembly. This modification is not necessary, because the holes do not control the amount of oil that will drain. The groove in the valve assembly controls the amount of oil. Any improvement in performance after this modification was probably from the use of a new diaphragm, seals or adjustments.
Also, reports show that the letters "PC" on the end of the 2P8802 Valve Assemblies have caused some confusion (problems). These letters are for identification purposes only. They do not mean that the valve assembly must be used only in a precombustion chambered engine. The 2P8802 Valve Assemblies with the letters "PC" are correctly used in several direct injection engines. If desired, the "PC" mark can be removed from the end of the valve assemblies to prevent any confusion in the future.
Diaphragm
Formerly, the 2P8804 (Black) and 1W4797 (Gray) Diaphragms were used. The former black diaphragm can become rigid and possibly crack. This can cause