Cummins/Onan — Timing Gears
Repair & overhaul
From a Cummins/Onan service manual — check it applies to your exact model before use.
Browse Cummins/Onan generators & specs →
Before you start
- Do not press on center pin.
Procedure
- If replacing either crankshaft or camshaft gear, install both new.
- To remove crankshaft gear, insert two long #10-32 steel screws into tapped gear holes and tighten alternately.
- Camshaft gear is pressed and keyed to camshaft; remove camshaft and gear as assembly after removing crankshaft gear lock ring and washer.
- Remove cylinder head, valve assemblies, anti-flicker breaker plunger, fuel pump, and tappets.
- Press camshaft out of gear using hollow tool over center pin; do not press on center pin.
- Governor ball spacer is press fit to camshaft gear.
- Align 'O' marks on gears when installing.
- Ensure thrust washer behind camshaft gear. Replace retaining washer and lock ring.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- timing marks must coincide
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.