VALVE GROUP 8J8374 - Caterpillar

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.
A special level setting may be required for satisfactory performance in some high altitude applications and in some applications where a cubic demand can be on the engine, such as a marine application.