Engine Problems
Engine Problems while in Operation
DIESEL ENGINE PROBLEMS: FUEL, AIR, STARTING, WIRING
Many cases of engine failure are a result of a relatively small number of faults so it’s often possible to get the motor running again within a few minutes. However, when diagnosing problems it’s important to work in a systematic fashion and avoid the temptation to jump to conclusions.
(Left) Bleeding the fuel with the primary bleed screw (Right) bleeding the fuel at the injector pump
With a fuel problem, for instance, it’s important to start by being sure there’s enough fuel in the tank – it’s very easy to assume the problem is elsewhere. Many gauges are inaccurately calibrated, so checking with a dipstick or sight gauge is more accurate. Yachts with shallow tanks squeezed under aft cabin berths should ideally keep them at least one-third full to avoid problems when heeled while motor sailing.
Other problems that may also result in similar initial symptoms – typically a loss of power – include a hull that’s badly fouled by marine growth, a propeller of the wrong size or pitch and plastic sheeting or netting around the propeller. Many larger and newer engines have integrated diagnostic systems, which should always be checked first in the event of a problem. However, smaller or older units are more likely to have no warning systems beyond the lights/buzzers for oil pressure, overheating and battery charging. On the plus side, their simplicity makes it relatively easy to trace and rectify faults.
Fuel and air problems
These can be a cause of failure to start, loss of power, or the engine stopping when under way. A basic diesel engine needs only a constant supply of clean fuel, plus air to provide oxygen for combustion. The amount of air needed is easy to under estimate – around one cubic meter per minute is required for every 10hp of engine power. Defective engine compartment ventilation, or clogged air filters, can therefore result in a loss of power.
DIESEL ENGINE PROBLEMS: FUEL, AIR, STARTING, WIRING
Many cases of engine failure are a result of a relatively small number of faults so it’s often possible to get the motor running again within a few minutes. However, when diagnosing problems it’s important to work in a systematic fashion and avoid the temptation to jump to conclusions.
(Left) Bleeding the fuel with the primary bleed screw (Right) bleeding the fuel at the injector pump
With a fuel problem, for instance, it’s important to start by being sure there’s enough fuel in the tank – it’s very easy to assume the problem is elsewhere. Many gauges are inaccurately calibrated, so checking with a dipstick or sight gauge is more accurate. Yachts with shallow tanks squeezed under aft cabin berths should ideally keep them at least one-third full to avoid problems when heeled while motor sailing.
Other problems that may also result in similar initial symptoms – typically a loss of power – include a hull that’s badly fouled by marine growth, a propeller of the wrong size or pitch and plastic sheeting or netting around the propeller. Many larger and newer engines have integrated diagnostic systems, which should always be checked first in the event of a problem. However, smaller or older units are more likely to have no warning systems beyond the lights/buzzers for oil pressure, overheating and battery charging. On the plus side, their simplicity makes it relatively easy to trace and rectify faults.
Fuel and air problems
These can be a cause of failure to start, loss of power, or the engine stopping when under way. A basic diesel engine needs only a constant supply of clean fuel, plus air to provide oxygen for combustion. The amount of air needed is easy to under estimate – around one cubic meter per minute is required for every 10hp of engine power. Defective engine compartment ventilation, or clogged air filters, can therefore result in a loss of power.