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Cummins/Onan — In-

For these Cummins/Onan models: 6JB, 7.5JB, J-Series (2-cylinder), J-Series (4-cylinder), JC.

Applies to: Cummins Onan 6Jb, Cummins Onan 7 5Jb

Procedure

  1. Before installing a new diaphragm, soak it in fuel. In- sert the diaphragm spring and soaked diaphragm into the pump body.
  2. Compress the rocker spring and install between the body and rocker arm.
  3. Assemble the cover to the body with notch marks lined up. Install the screws but don’t tighten. Push the rocker arm in. fuli stroke and hold in this position to flex the diaphragm. NOTE: The diaphragm must be flexed or it will deliver too much fuel pressure. 4, Tighten the cover screws altetnately and securely, then release the rocker arm. AMBIENT TEMP. (°F) 60 65 70 75 80 85 90 95 100 CHOKE OPENING (Inches) 1/8 9/64 §/32 11/64 3416 13/64 7/32 15/64 \/4 SPEC C-R TIEIO cuowe oveninc 4 a _ {Se
  4. Install the pump on the engine and repeat the pressure: test. CHOKE (Gasoline fuel system). Remote starting plants use an automatic electric choke (Fig.

Source: manual:967-0500 Onan JB JC (spec A-T) Genset Service manual MAGNECITER END (11-1971).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.