Cummins/Onan — Worn - Spark plug service life used up.

For these Cummins/Onan models: BGM, NHM.

Applies to: Cummins Onan Nhm

Procedure

1. 1. Park the vehicle in a well-ventilated area, leave
2. 2. Remove one of the spark plugs.
3. 3. Reconnect the spark plug cable and lay the
4. 4. Crank the engine and observe the spark. A
5. 1. Remove both spark plug cables from the igni-
6. 2. Connect the positive (+) side of a voltmeter to
7. 3. Remove all leads from the positive (+) terminal
8. 4. Use a jumper to connect the red lead of the igni-
9. 5. Rotate the engine clockwise using a socket
10. 1. Remove all wires attached to the ignition coil.
11. 2. Remove the coil from the engine.
12. 3. Inspect the terminals for corrosion, looseness,
13. 4. Clean the outside of the coil with a cloth damp-
14. 5. Measure primary coil resistance (across the
15. 6. Measure secondary coil resistance (across th
16. 1. Start the genset and let it warm up.
17. 2. Stop the genset and remove and inspect the
18. 3. Insert the compression gauge nozzle into one
19. 4. Repeat the test on the other cylinder.
20. 5. Refer to Section 9. Engine Block Assembly if

Source: manual:965-0531B Onan BGM NHM Marquis series RV Genset Service manual (02-1991).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.