PUMP GP-PISTON 2582405 - Caterpillar

All D348, D349 and 3400 Series EnginesSUPPLEMENT: 02/16/83ENGINE NEWS, DECEMBER 15, 1982, PAGE 1.In the article, "Improvements Made To Fuel Ratio Control," change the second sentence, in the third paragraph, under the topic "Description of Change" to read: "The new seal is made of a Viton material and causes less friction between itself and the housing."
--------------- END SUPPLEMENT ---------------Reference: Engine News, March 17, 1982, Page 1. The article "New Diaphragm Used In Fuel Ratio Control", tells about the use of a new gray silicone diaphragm in the control group.Description of Change: Several improvements have been made to the fuel ratio control groups to increase service life and improve performance (faster reaction time). These improvements include new valve assemblies, a lip-type seal, spring retainer, and an improved diaphragm. The two new valve assemblies have smoother bore surfaces for a better fit with the 2P8939 Valve. This smoother surface will improve performance.
A new lip-type seal is used with the new valve assemblies. The new seal is made of a Viton material and causes less friction between itself and the housing. Formerly, two seals were used. These seals have worn the housing in some applications.
The new spring retainer is made from stamped metal. It must be installed with the convex side toward the air chamber. If the new spring retainer is not installed correctly, the fuel ratio control will not work correctly.
An improved diaphragm is now used. This diaphragm now has a rib (bead) around the inside diameter to make a better seal around the retainer assembly. This will prevent leakage of oil into the air chamber. The part number of the diaphragm did not change, but for identification purposes the color was changed to white. The former diaphragm was gray in color.
Adaptable As: The new parts are direct replacements for the former parts as shown in Chart A. The parts are in effect with the serial numbers shown in Chart B. It is our recommendation to put an "N" mark on any fuel ratio controls that have had the new parts installed. This "N" mark will make it easier in the future to tell which fuel ratio controls have the new parts. 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.
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