Northern Lights — Soundshield Assembly and Installation
Installation · M673L3/LD3 soundshield enclosure
From a Northern Lights service manual covering: M673, M673LD3, M673LD3 / M673L3. Check it applies to your exact model before use.
Applies to: Northern Lights M673, Northern Lights M673LD3
Before you start
- Generator sets with wet exhaust installed near or below the vessel's water line must use a siphon break to prevent backflow of water into the engine, which can ruin the engine and possibly sink the vessel
Procedure
- Inspect all components for damage and check the packing list before assembly
- Loosen and rotate down original factory lifting points below the highest point on the engine, then retighten
- Select mounting location per IM1000 Installation Manual on a rigid, flat surface above a strong structure
- Position the enclosure so its left side and rear are 6 in recommended (4 in minimum) from bulkheads, avoiding corners with blocked overhead
- Install toe brackets to each corner of the genset base flanges with machine screws, flat washers, and nylock hex nuts
- Install the four vertical extrusions with bolting assemblies; leave loose enough for adjustment during building
- Loosely install front and left-hand side panel retainer blocks to the vertical extrusions
- Position the pre-assembled top frame with triangular penetration plate toward the front and tighten all bolting assemblies progressively
- Install the junction box support cover into the cavity of the support bracket until firmly engaged
- Install the rear sound shield panel, engaging top retaining clips and securing the bottom with bolts, flat washers, and shoulder washers
- Bend the intake air snorkel hose into the rear panel notch without kinking or restricting airflow
- Connect exhaust, sea water, fuel, DC control harness, battery, and AC output leads through the rear panel holes
- If installing a siphon break, replace hole plugs with rubber grommets and route hoses per the IM1000 Installation Manual
- Start the generator set and run under load to check for leaks of fuel, water, or exhaust gas
- Install left side, front, top, and right side panels, and insert foam blocks into the base pan mounting foot pockets
Specs & values
- Minimum panel perimeter clearance approximately 1/32 in
- Siphon break mounted a minimum of 12 in above the vessel's loaded waterline
- Fuel suction coupling 1/4" NPT (forward), fuel return coupling (aft)
Full service-parts list: Northern Lights M673 →, Northern Lights M673LD3 →
Source: Northern Lights 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.