Cummins/Onan — Flowing the Pump (PLB timing)
Adjustments · PLB injection pump
From a Cummins/Onan service manual covering: 2.5A, 2.5L, 2.7 AJ, 4.0CCK, 6.0CCKB, 6.5 NH, JC - 3CR / 96 T. Check it applies to your exact model before use.
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Procedure
- Install pump with .006-inch (0.15 mm) shims between pump and pad.
- Loosen delivery valve holder to relieve pressure on spring.
- Rotate flywheel to about 15 degrees before port closing point.
- Operate transfer pump hand primer lever and rotate flywheel slowly clockwise until fuel stops coming out of pump outlet.
- Measure distance from port closing point to PC mark and add shims per table.
- Install pump.
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.