Cummins/Onan — Chatter Test

For these Cummins/Onan models: 12, 0MDJC-3CR, 12.0MDJF-53CR, 15.0MDJF-3cR, 3omDJaiR, 4.0MCCK-3cR, 6.0MDJE-53CR, 6.5MCCK-3CR, 6.OMDJE-S18R, 612-4792, 7.SMOJE-18R, ISOMDJF-3GR.

Applies to: Cummins Onan 12 0Mdjf 53Cr, Cummins Onan 15 0Mdjf 3Cr, Cummins Onan 3Omdjair, Cummins Onan 4 0Mcck 3Cr, Cummins Onan 6 0Mdje 53Cr, Cummins Onan 6 5Mcck 3Cr, Cummins Onan 6 Omdje S18R, Cummins Onan 7 Smoje 18R, Cummins Onan Isomdjf 3Gr, Cummins Onan Mcck Spec H, Cummins Onan Mdje 8, Cummins Onan Spec H, Cummins Onan Tsmdje 3Cr

Procedure

1. 1. Operate hand lever downward (1 or 2 nozzle opening cycles per second) until nozzle ejects a stream of fuel with a soft chattering sound.
2. 2. Take pressure readings trom gauge.
3. 3. Slightly increase hand lever movements (2 or 3 nozzle opening cycles per second), the stream velocity should increase and create a hissing
4. 4. Accelerate lever movements to 4-6 nozzle open- ing cycles per second. Thenozzleshould createa shrill whistling sound and a spray pattern aoe PATTERN attuttitio becorrect The pressures between nozzle opening and full lift causes the fuel to emerge in a stream, change to flag-like formations, and finally reach atomized spray pattern at full lift with lever movements producing 4-6 nozzle opening cycles per second. See Figure 3-

Source: manual:932-0405 Onan Marine Genset MCCK MDJA MDJC MDJE MDJF Training Manual (07-1979).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.