Northern Lights M773L — Injector Removal and Installation
Repair & overhaul · fuel injectors
For the Northern Lights M773L, from the Northern Lights operator's manual.
Applies to: Northern Lights M773L
Before you start
- Escaping diesel fuel under pressure can penetrate skin and cause serious injury.
- Do not use hands to check for leaks; use cardboard or wood.
Procedure
- Clean loose dirt from around injectors and fuel lines.
- Relieve high pressure by loosening delivery line flare nuts at each injector.
- Remove delivery lines as an assembly; do not remove spacers; cover all open ends.
- Remove return line retaining bolts and remove the return line.
- Unscrew and remove the injectors; do not use pry bars.
- Discard copper sealing washers from the head; cover holes to keep dirt out.
- Install new copper sealing washers, screw in injectors and tighten to 43 or 50 ft/lbs (6 to 7 kgm).
- Install return line with new copper seals; tighten retaining bolts to 22 - 30 ft/lbs.
- Install delivery lines loose at injectors for bleeding, fill lines with hand primer, tighten, start and check for leaks.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Injector torque 43 or 50 ft/lbs (6 to 7 kgm)
- Return line retaining bolts 22 - 30 ft/lbs
Full service-parts list: Northern Lights M773L →
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.