Known Marine Engine Problems: Yanmar, Volvo Penta, Mercury Verado, Yamaha, Suzuki, Honda, Engine Hours

Hours and condition

Boat engine hours

How many hours a marine gas or diesel engine usually runs before a major overhaul, why hours alone don't decide condition, and what to check on a used engine: service records, oil analysis trends, compression, smoke and the cooling system.

What to check

Diesel engines

DIESEL ENGINES

Yanmar GM series

Known problems on Yanmar GM series sailboat diesels and where to look: the exhaust elbow that corrodes from the inside and sends water back into the cylinders, valve seats and compression, the air filter, soft engine mounts, and fuel knock.

What to check

DIESEL ENGINES

Volvo Penta D2

The known weak point on Volvo Penta D2 sailboat and small motorboat diesels: galvanic corrosion where the steel exhaust elbow meets the aluminium heat exchanger, which can leak exhaust into the boat. Where to look and how to write it up.

What to check

DIESEL ENGINES

Yanmar 3JH and 4JH

What to check on Yanmar JH series sailboat and trawler diesels: the mixing elbow Yanmar says to replace every 500 hours or 2 years, the turbo on the 4JH TE and HTE that loses power when dirty, and hoses. Where to look and how to write it up.

What to check

Gas engines and sterndrives

GAS ENGINES AND STERNDRIVES

Sterndrives

Known problems on MerCruiser and Volvo Penta sterndrives and where to look: cast aluminium drives that corrode once the paint is breached, wasted anodes, stray current from electrical faults, bad antifouling jobs, and USCG recalls on Alpha and Bravo drives.

What to check

GAS ENGINES AND STERNDRIVES

Gas inboard engines

Known problems on gas inboard and sterndrive engines such as the MerCruiser 4.3 and 5.7 and Volvo Penta 4.3 and 5.7, and where to look: exhaust risers that corrode and let water into the engine, cooling and coolant mistakes, head gaskets, and USCG recalls.

What to check

GAS ENGINES AND STERNDRIVES

Volvo Penta

Known problems and recalls on Volvo Penta engines and drives and where to look: the EVC 2 software recall on V6 and V8 gasoline engines, hydraulic hoses on D4 and D6 diesels with DPH sterndrives, and USCG campaigns on gas engines and larger diesels.

What to check

Outboards

OUTBOARDS

Mercury Verado

Known problems and recalls on Mercury Verado outboards and where to look: the corroding shift bell crank stud on L6 Verados, the V12 steering position sensor recall, other USCG campaigns, and how to check a used Verado's recall status by serial number.

What to check

OUTBOARDS

Yamaha four-stroke outboards

Known problems and recalls on Yamaha four-stroke outboards and where to look: the throttle linkage campaign on F200 and F225, the ignition coil recall on V MAX SHO models, the exhaust corrosion claims against first generation F-Series motors, and USCG campaigns.

What to check

OUTBOARDS

Honda outboards

Known problems and recalls on Honda BF four-stroke outboards and where to look: the V6 shift actuator link rod that can leave the boat stuck in forward gear, the ACG belt that can stop the engine, vapour separator fuel leaks, and an older throttle wiring fault.

What to check

OUTBOARDS

Suzuki DF140

Suzuki's own service campaigns on the DF90 to DF140 outboards, with serial ranges: an undersized water pump sleeve that could overheat the engine and an ECM fault that silenced the water in fuel alarm, plus what to check for corrosion.

What to check

Generators

GENERATORS

Marine generators

Common problems on marine generators and where to look: starting power, clogged fuel filters on gensets that sit unused, raw water flow and strainers, generators mounted low in wet bilges or squeezed between the engines, and carbon monoxide.

What to check

Know the engine before you start it

Hours and condition

Boat engine hours

Diesel engines

Yanmar GM series

Volvo Penta D2

Yanmar 3JH and 4JH

Gas engines and sterndrives

Sterndrives

Gas inboard engines

Volvo Penta

Outboards

Mercury Verado

Yamaha four-stroke outboards

Honda outboards

Suzuki DF140

Generators

Marine generators

Read out the gauges. Axsail writes them up