Many military generators have check valves in the fuel line system, often immediately after all of the filters, strainers, but before the injector pump. This prevents fuel from flowing backwards in the system and also helps the system hold its prime. The MEP-002A and MEP-003A units have a check valve located after the third filter in an elbow near the oil pressure gauge. It is important to ensure that this check valve is working properly. It can stick if a unit has sat for multiple months without running. Usually a blast of compressed air and some clean diesel can help un-stick the valve. GMG recommends exercising your generator monthly for 1-2 hours at rated speed. Do not let your unit warm up or warm down. Ideally a load should be placed on the unit during exercising as well.
The NSN part number for this check valve is: 4820-01-049-1322
The manufacturer and part number is: 22962B (14834)
Only 1 check valve is used on the MEP-002A and MEP-003A units.