Which engine was fitted to the Hallberg-Rassy Rasmus 35, and what should I check?
I'm looking at a Hallberg-Rassy Rasmus 35 advertised with its original 75hp Volvo Penta. Which engine should that be, and what should I check before trusting it for cruising?
Answer
The Hallberg-Rassy Rasmus 35 most commonly had a four-cylinder Volvo Penta MD21 diesel, usually advertised as 75hp, though the engine version and rating convention affect the quoted output. Check the identification plate first, then cooling-system corrosion, cold starting, the exhaust elbow and gearbox; condition and maintenance matter far more than age alone.
Identify the engine
The Rasmus 35 dates from the late 1960s and 1970s, so check any advertised "original Volvo" against its plate and service records. Many boats have been repowered. Paint colour or an old instrument panel proves very little.
The MD21 family uses a Peugeot/Indenor-derived diesel with Volvo Penta marine equipment. Do not confuse it with later Perkins-derived Volvo engines fitted to other Hallberg-Rassy models. Automotive interchangeability does not automatically extend to the seawater pump, exhaust manifold, heat exchanger or gearbox.
- Photograph the engine model, suffix and serial number.
- Record the gearbox identification separately.
- Establish whether the cooling arrangement is original, modified or replaced.
- Ask for invoices covering cooling-system work, injectors, exhaust components and winterisation.
Do not use generic torque settings or order a head gasket simply against "Rasmus 35". Use the exact engine version and its workshop manual to establish those details.
Check cooling and exhaust
Start with cooling. Corroded or unobtainable marine components can make an otherwise sound engine uneconomic to repair. Inspect the seawater inlet, strainer, pump, hoses, heat exchanger where fitted, and water-injection exhaust elbow.
- With the engine cold, check coolant where applicable and look for rust trails, salt deposits and previous leak repairs.
- Inspect the seawater-pump cover and shaft area for leaks; ask when the impeller was last changed.
- Have the exhaust elbow removed if its condition is unknown. External paint can hide internal restriction or corrosion.
- During a loaded sea trial, watch temperature and exhaust-water discharge after the engine has warmed through.
An engine that stays cool alongside may overheat when driving the boat. Possible causes include restricted passages, a damaged impeller, a fouled heat exchanger or an obstructed elbow. Bubbles or repeated coolant loss need investigation; they do not justify an immediate diagnosis of head-gasket failure.
Stop the engine and isolate the starting circuit before putting hands near belts, couplings or the seawater pump.
Cold start and sea trial
Ask the seller to leave the engine cold before your visit. Feel the block before starting: warming the engine can conceal poor compression, weak cranking or starting difficulties.