Cummins/Onan — Draining/Replacing the Fuel Filter
Maintenance
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MDKB, Cummins/Onan MDKBH
Before you start
- Diesel fuel is combustible; keep sources of ignition away.
Parts for this job
- 1522143081 Fuel filter — Cummins/Onan MDKB Amazon eBay $37.58 KuduParts $13.00 FridayParts $15.69
- 149-2106 Fuel filter — Cummins/Onan MDKBH Amazon eBay $34.99 NAPA $61.61 KuduParts $68.00
Part numbers from the service-parts lists for Cummins/Onan MDKB, Cummins/Onan MDKBH. Verify against your serial number before ordering; some links are affiliate links.
Procedure
- Disconnect the negative battery cable and close any fuel supply and return valves.
- Open the front access door and drain about 1/2 cup (120 ml) by removing the drain plug at the bottom of the filter.
- Re-install the drain plug.
- Spin off the old filter with a filter wrench and dispose of it properly.
- Clean the filter base contact surface, lubricate the new filter gasket and spin the new filter on hand tight.
- Prime the engine for at least 30 seconds to fill the new filter.
- Run the genset and check for leaks; tighten the filter by hand if necessary.
Tools required
- filter wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Prime the engine for at least 30 seconds
Full service-parts list: Cummins/Onan MDKB →, Cummins/Onan MDKBH →
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.