Cummins/Onan 20W-20 — BUTTON WITH CODE LETTER

For the Cummins/Onan 20W-20.

Applies to: Cummins Onan 20W 20

Procedure

1. Remove old pump.
2. Determine total pump flange button thickness for old pump. a. Write down dimension given on old pump flange. See Example: Port closing dimension of old pump Button thickness of old pump Total Port closing dimensions of new pump Required button thickness o f new pump b. Remove old pump timing button. Inches (mm)

Source: manual:974-0251 Onan RDJF Engine Service and Parts Manual (3-1980).pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.