Northern Lights — Changing raw water pump impeller (SP17, marine)
Maintenance
From a Northern Lights owner's manual covering: 643/673, M643, M673, NL643, NL673. Check it applies to your exact model before use.
Applies to: Northern Lights M643, Northern Lights M673, Northern Lights NL643, Northern Lights NL673, Northern Lights L643 / L673 engine
Before you start
- Place protection under the screwdrivers so the pump housing is not damaged.
- Keep an extra impeller and cover gasket in reserve on board.
Procedure
- Change the seawater pump impeller every 600 hours, or as needed.
- Remove the pump end cover.
- Pry out the impeller using needle-nose pliers or two screwdrivers.
- Be sure all pieces of a failed impeller are removed.
- Clean the inside of the housing.
- Press in the new impeller and place the sealing washers in the outer end of the impeller center.
- Replace the cover using a new gasket.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Full service-parts list: Northern Lights M643 →, Northern Lights M673 →, Northern Lights NL643 →, Northern Lights NL673 →
Source: Northern Lights owner's 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.