Vetus M4.35K Keel-Cooled Inboard Marine Diesel Engine

Description

Navigating shallow muddy canals causes severe raw water impeller blockages in traditional heat exchanger engines. The Vetus M4.35K Keel-Cooled Marine Diesel Engine eliminates raw water ingestion through a 4-Cylinder 1.8L block generating 29.5BHP at 2,800 RPM. Operators must purge air from the external skin-tank plumbing on startup and maintain adequate anti-freeze concentrations to prevent internal corrosion.

Casting construction features an ASTM gray cast iron monobloc with parent cylinder bores and an overhead-valve cylinder head. The electrical plant runs a 12V negative ground system powered by a 1.7 kW electric starter and a 110A marine alternator. Dry mass spans 309 lbs without marine transmission. The physical chassis envelope requires 26.8in length, 18.9in width, and 22.6in height, with a lube oil sump holding 1.27 US gal.

Key Features of Vetus M4.35K

Inland waterway transport skippers buy Vetus M4.35K keel-cooled marine diesel engines to avoid overheating in silty weed-choked river cuts. The unit provides an ideal inland waterway narrowboat propulsion engine solution for craft up to 50ft.

• Skin-tank keel-cooling circuit keeps mud, sand, and canal weeds out of the engine block.
• Naturally aspirated 4-Cylinder design yields low vibration and smooth torque delivery across canal speed limits.
• Acoustic top cover suppresses valvetrain clatter in small narrowboat stern decks.
• Bosch-type in-line multi-plunger injection pump ensures cold-start reliability in freezing temperatures.
• High-capacity header tank maintains constant positive coolant head pressure across steep locks.
• Heavy-duty 110A marine alternator charges large domestic battery banks at canal cruising speeds.
• Dedicated bellhousing mounts flexible marine dampers compatible with PRM 125 transmissions.

Keel-Cooled Dyno Output Thermal Performance

Dynamometer bench verification proves 29.5BHP continuous power and 58 ft-lbs of shaft torque at 2,800 RPM, reaching 33.0BHP at 3,000 RPM. Dry exhaust gas collectors hold temperatures under 910°F before entering the boat exhaust line. Skin-tank circulation loops stabilize engine coolant temperatures at 180°F under sustained full-power towing conditions. Engine lube oil pressure maintains 50 PSI at cruising RPM, while crankshaft journal concentricity checks confirm runout below 0.0004in TIR across all bearing surfaces.

Field Usability Protocols Installation Boundaries

Mechanical control linkages require 4 lbs of manual effort to sweep the fuel governor lever across its control throw. This keel-cooled engine is not designed for open offshore waters requiring wet exhaust cooling, high-speed skiffs, or planing launches. Never select this inland waterway narrowboat propulsion engine for steel narrowboat hulls exceeding 50ft or craft lacking verified skin-tank cooling channel surface area.

• Drain engine lube oil and replace spin-on cartridge filters every 150 operating hours.
• Check skin-tank coolant expansion levels and hose connections every 12 months.
• Verify overhead valve lash clearances and reset to 0.010in cold every 500 operating hours.

Factory Warranty Marine Crate Manifest

Vetus warrants this keel-cooled propulsion package with a 5-Year leisure and 3-Year commercial marine manufacturer warranty. The factory unboxing manifest contains the bobtail engine core, 12V 1.7 kW starter, 110A alternator, flexible vibration mounts, pre-wired instrument harness, coolant temperature sender, oil pressure switch, and operator maintenance manuals.