Cummins/Onan — To determine PC, proceed as follows:

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. Remove one high pressure line (both ends), and the corresponding delivery valve holder, spring, Leave gasket and seat in pum; the spring and volume reducer in a clean container of fuel unt rentals. DELIVERY PIPE DELIVERY VALVE HOLOER DELIVERY VALVE SUCTION CHAMBER Port PLUNGER BARREL KNOCK PIN ‘CONTROL SLEEVE LOWER SPRING. SEAT GUIDE PIN
2. 2. Re-install delivery valve holder (without spring and volume reducer)
3. 3. Install high pressure line on delivery valve outlet so that drops of fuel can be easily counted and collected in a receptacle at the open end of the ine. Move the fuel control arm toward the front of the engine to full fuel range. the plunger out of the way.
4. 5. Manually operate transfer pump lever to provide Rotate flywheel clockwise very slowly by hand until fuel stops flowing from open line even though transfer pump operation is continued. Rotate flywheel counterclockwise until fuel flows freely; then, clockwise very slowly to position where fuel drops can be counted at one drop per second with the transfer pump operating, ° ‘This is the PC point; it should be marked on the flywheel ‘opposite the timing pointer.
5. 8. After flow timing is completed, remove high reinstall delivery valve, spring, and volume reducer. ‘Make sure all parts are clean.
6. 9. Reinstall delivery valve holder and torque Bryce holder to 44-47 tt. Ibs. (60-64 Nem). If fuel leakage ‘occurs, replace the delivery valve gasket. zzle. Using the same procedure, flow timing can be performed on the other cylinder to determine PC or the difference in degrees between cylinders;
7. 2. 5 degrees is allowable. ENGINE PERFORMANCE Engine performance at 1500 and 1800 rpm varies limits wher ‘occurs be 14° ang 22" BIC. Generally, teardsd timing results in lower smoke but higher fuel consumption; and vice versa when timing is advanced.

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.