Cummins/Onan — Injection Nozzle Cleaning
Maintenance
From a Cummins/Onan service manual — check it applies to your exact model before use.
Browse Cummins/Onan generators & specs →
Before you start
- Never use hard or sharp tools, emery paper, grinding powder or abrasives of any kind on nozzles.
Procedure
- Soak each nozzle in fuel to loosen dirt.
- Clean inside with a small strip of wood soaked in oil.
- Clean spray hole with a wood splinter.
- Use a brass scraper to remove hard carbon deposits from nozzle body valve seat.
- Polish the valve seat using a round pointed stick dipped in tallow.
- Use a special hooked scraper to clean the nozzle pressure chamber gallery.
- Clean nozzle valve and polish with tallow and a wooden polishing fixture; remove all traces of tallow.
- Examine nozzle valve and body with a magnifying glass; replace valve and body if erosion or scoring is found.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
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.