Cummins/Onan — Sea Water Pump Reassembly
Repair & overhaul
From a Cummins/Onan service manual covering: 4.5 MCE, 5.0 MCE, 6.5 MCE. Check it applies to your exact model before use.
Applies to: Cummins/Onan 4.5 MCE, Cummins/Onan 5.0 MCE, Cummins/Onan 6.5 MCE, Cummins/Onan MCE engine
Before you start
- Neoprene impeller disintegrates in seconds if pump run dry.
Procedure
- Press in new water seal; lubricate bore and seal lip with vasoline.
- Press new bearings onto shaft from pulley end; snap retaining ring into place.
- Install plastic washer and O-ring; insert shaft assembly until it bottoms.
- Assemble wear plate, cam and impeller; lubricate wear surfaces.
- Secure pump cover and gasket.
- Secure pulley and mount pump; align pulleys and adjust belt tension.
Tools required
- Pliers Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Belt deflection approximately 1/8 in. (3 mm) with 7 lb (3 Kg) force
Full service-parts list: Cummins/Onan 4.5 MCE →, Cummins/Onan 5.0 MCE →, Cummins/Onan 6.5 MCE →
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.