Northern Lights — Changing the raw water pump impeller (SP17)
Maintenance · Seawater pump
From a Northern Lights operator's manual covering: M16, M20, M20C, M844, M844L, ML844, ML844L, NL844. Check it applies to your exact model before use.
Applies to: Northern Lights M20C, Northern Lights M844, Northern Lights M844L, Northern Lights ML844, Northern Lights ML844L, Northern Lights NL844, Northern Lights 844 / 844L engine, Northern Lights 844L engine
Before you start
- Place some kind of protection under the screwdrivers in order not to damage the pump housing.
- Make sure that there is always 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. Remove all pieces of failed impeller.
- 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
- Needle-nose pliers or two screwdrivers Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Full service-parts list: Northern Lights M20C →, Northern Lights M844 →, Northern Lights M844L →, Northern Lights ML844 →, Northern Lights ML844L →, Northern Lights NL844 →
Source: Northern Lights operator'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.