Cummins QSB6.7 Commercial Lobster Boat Marine Diesel Engine

Description

Lower displacement hull fuel burn using the Cummins QSB6.7 Lobster Boat Marine Engine built for high-speed trap hauling cycles. This 6.7-liter inline six diesel outputs 425 brake horsepower at 3000 RPM under light commercial duty ratings. Common-rail fuel injection combines with four-valve cylinder heads to drive fast sprint speeds between distant offshore trap strings.

Formed from compacted graphite iron, this block integrates parent-bore cylinders and a forged steel crankshaft balanced by seven main bearings. Engine utilities feature a 70/30 cupronickel shell heat exchanger protected by replaceable zinc anodes. Fuel connections require a #8 JIC flare inlet while raw sea water intake uses a 2.5-inch hose barb. Total dry engine weight equals 1,450 lbs, matched with an SAE #3 bell housing and an aluminum oil pan holding 15 quarts.

Key Features of Cummins QSB6.7

Down East lobster fishermen buy Cummins QSB6.7 inboard engine models to combine fast trap-hauling speeds with economical trolling power. This propulsion unit provides fast throttle response to maneuver lobster hulls between tight trap buoys in breaking swells.

• High-pressure 1,800-bar fuel injection meters clean fuel charges to eliminate soot while trolling trap lines.
• Variable turbo boost geometry refines QSB6.7 fuel injection pressure to achieve fast planing speeds with loaded decks.
• Bronze raw water pump circulates 50 gallons per minute through the sea water aftercooler.
• Torsional crankshaft vibration damper preserves marine gear clutches during repeated shifts while pulling traps.
• Top-mount spin-on oil filters allow clean lube swaps without spilling fluid into tight bilges.
• Water-jacketed exhaust riser maintains engine box surface temperatures within safe commercial limits.
• CAN-bus digital gateway feeds fuel metrics and water temperature readouts straight to pilot displays.

Torque Characteristics Marine Thermal Boundaries

Generating 950 lb-ft torque at 2,000 RPM, this lobster boat engine accelerates displacement Down East hulls onto plane even with 200 lobster traps stacked on deck. Engine coolant holds steady between 165°F and 185°F under continuous sprint cycles. Common-rail injection at 1,800 bar ensures uniform combustion across all six cylinders. Heat rejection to the sea water exchanger measures 13,500 BTU per minute at wide-open throttle. Specific fuel consumption equals 0.365 lb per horsepower-hour at cruise, holding operating fuel costs down during regular offshore runs.

Stringer Mount Wet Exhaust Integration

Engine bed stringers require at least 2.5 inches vertical drop to clear the deep front sump during wave impacts. Wet exhaust plumbing mandates a 5.0-inch waterlock hose meeting ABYC P-1 marine rules. Heavy vibration shear mounts keep the engine stable while preventing shaft misalignment with the transmission output coupling.

Shift Checks Operational Maintenance Protocol

Smooth electronic throttle handles provide fine propeller control while working around lobster pot lines. This marine propulsion engine is not engineered for high-rpm surface piercing drives, silt-laden shallow canal dredging, or continuous unmonitored wide-open throttle sprints exceeding intermittent duty limits.

• Inspect raw sea water pump impellers and clear debris from the hull intake strainer each shift.
• Drain water separation canisters and examine crankcase lube level on the dipstick every 50 hours.
• Replace secondary fuel filter cartridges and inspect zinc pencils inside the heat exchanger every 250 hours.

Commercial Warranty Factory Crate Manifest

Cummins covers this commercial lobster boat engine with a 2-Year or 2,000-Hour marine propulsion warranty. The crated package contains the complete base engine block, four resilient marine mounts, an electronic pilot house harness, an oil drain siphon kit, and a comprehensive factory technical service manual.