Cummins/Onan — Raw Water Pump Impeller Replacement - Minor Service Kit
Maintenance
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MDKAD, Cummins/Onan MDKAE, Cummins/Onan MDKAF
Before you start
- Petroleum-based greases will chemically attack the neoprene impeller. Do not use petroleum-based greases to lubricate the impeller.
Procedure
- Cover all electrical components beneath pump to protect from draining water.
- Remove three capscrews holding cover, O-ring seal, and rubber impeller.
- Use two pairs of pliers to grip two opposite vanes to remove impeller; note direction of vane bend.
- Install replacement impeller with same directional bend; align keyway to key and push in until flush against housing end.
- Reassemble O-ring, cover and capscrews. Ensure woodruff key fits in impeller key slot. Lubricate impeller with water, silicone lubricant or soapy water.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Full service-parts list: Cummins/Onan MDKAD →, Cummins/Onan MDKAE →, Cummins/Onan MDKAF →
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.