How often should a marine diesel be serviced?
Use the exact manual and whichever limit comes first, hours or calendar time. There is no safe universal interval. Low-hour engines still age internally and externally.
Is a saildrive less reliable than a shaft?
Not automatically. Saildrives add a diaphragm, aluminium underwater housing and model-specific corrosion controls. Shaft drives add alignment, a shaft seal and bearings. Condition and documented maintenance matter more than stereotypes.
Should I lock the propeller while sailing?
Follow the exact gearbox, saildrive and propeller instructions. Some specify freewheeling, some a gear position and some prohibit particular practices.
Can I run a diesel at idle to charge batteries?
It may charge poorly at idle and create extended light-load operation. Alternator output, engine guidance and battery charging design decide whether it is sensible.
What causes black smoke?
Usually too much fuel for available air or load: fouled or oversized propeller, restricted intake or exhaust, turbo or injector fault. Diagnose rather than adjusting the fuel system.
Why is my engine overheating only at high rpm?
Cooling flow may be marginal, the heat exchanger or exhaust may be restricted, or the engine may be overloaded. Check attainable rpm, raw-water flow and propeller condition.
How much fuel does a yacht diesel use?
Small yacht auxiliaries can vary widely with size and load. Use the model fuel curve, then measure litres per hour and speed on the boat. Calculate range with usable fuel and reserve.
Can I service a common-rail engine myself?
Owners can perform specified routine tasks if competent, but must never open a pressurised high-pressure circuit. Electronic diagnosis and injection work usually need trained support.
Is white exhaust always a head gasket?
No. Cold vapour, unburned fuel, low compression, injector faults, steam and water ingress can look white. Context and testing matter.
Should I replace an old engine before offshore cruising?
Age alone does not decide it. Assess compression or crankcase condition where warranted, oil trends, cooling and exhaust corrosion, parts support, leaks, installation quality and repair history.
Can I install a larger engine during a repower?
Only after checking structure, weight, beds, drive or shaft torque, gear ratio, propeller, exhaust, cooling, ventilation, registration, plate information and insurance.
Do I need a marine generator?
It depends on peak AC loads, daily energy, climate, battery capacity, solar, alternator output and acceptable run time. Many boats can avoid one; high air-conditioning or galley loads may justify one.
Why does my fuel filter keep blocking?
The tank likely contains water, sludge, microbial growth or degraded fuel. Replacing filters repeatedly does not remove the source.