ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – 006-012   Fuel Drain Line Restriction

Obtain a M12 banjo pressure gauge tool, Part Number 4918413.

A banjo-style pressure gauge adapter may be used to measure pressure or vacuum at any point in the low-pressure fuel system where a banjo bolt exists at a fuel line.

The engines use M12 x 1.5 banjo bolt connections. Part Number 4918413 may be used for measurement of drain line restriction (pressure) at the fuel drain manifold.

Make a banjo bolt pressure gauge tool by drilling and tapping the hex face of a M12 x 1.5 banjo bolt, Part Number 3903035, or equivalent.

Drill and tap the banjo bolt to the size of Compuchek™ fitting, or other hose union, being used (example 1/8-inch NPT Compuchek™ fitting, Part Number 3377244, or M10 Compuchek™ fitting, Part Number 3824842).

Assemble the banjo pressure gauge adapter.

1. Install the Compuchek™ fitting, Part Number 3377244, or other type fitting in the hex face of the banjo bolt.
2. Attach a hose or pressure gauge to the banjo pressure adapter.

Install the M12 banjo pressure gauge adapter in place of the injector drain line banjo at the fuel drain manifold.

Install the M12 banjo pressure gauge adapter in place of the banjo bolt that attaches the injector drain line to the electric lift pump drain manifold (CAPS fuel systems).

Install a 0 to 762 mm Hg [0 to 30 in Hg] pressure gauge at the M12 banjo pressure gauge adapter.

CAUTION  Use caution when disconnecting or removing fuel lines, replacing filters and priming the fuel system that fuel is not spilled or drained into the bilge area. Do not drop or throw filter elements into the bilge area. The fuel and fuel filters must be discarded in accordance with local environmental regulations.

On QSC8.3 engines, install a Compucheck™, or other type fitting, in the fuel outlet side of the fuel cooler, if one is not already installed.

Connect a 0 to 762 mm Hg [0 to 30 in Hg] pressure gauge with a flexible hose at the fuel outlet fitting.

CAUTION  Use caution when disconnecting or removing fuel lines, replacing filters and priming the fuel system that fuel is not spilled or drained into the bilge area. Do not drop or throw filter elements into the bilge area. The fuel and fuel filters must be discarded in accordance with local environmental regulations.

On QSL9 engines with sea water cooling, install a Compucheck™, or other type fitting, in the fuel outlet side of the fuel cooler, if one is not already installed.

Connect a 0 to 762 mm Hg [0 to 30 in Hg] pressure gauge with a flexible hose at the fuel outlet fitting.

CAUTION  Use caution when disconnecting or removing fuel lines, replacing filters and priming the fuel system that fuel is not spilled or drained into the bilge area. Do not drop or throw filter elements into the bilge area. The fuel and fuel filters must be discarded in accordance with local environmental regulations.

NOTE: QSL9 engines with keel coolers do not have fuel coolers.

On QSL9 engines with keel cooling, install the M12 banjo pressure gauge adapter in place of the injector drain line banjo at the fuel drain manifold.

Connect a 0 to 762 mm Hg [0 to 30 in Hg] pressure gauge with a flexible hose at the M12 banjo pressure gauge adapter.

Operate the engine at rated speed and no load.

Observe the reading on the gauge.

Fuel Drain Line Pressure

If the drain line pressure is out of specification, check for bends or kinks in the drain lines. Look for places where the OEM fuel lines may be pinched by wire ties or p-clips. Check for blocked fuel tank vents.

• Remove all test fittings and install the drain lines. Refer to Procedure 006-013 in Section 6.