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A well-charged battery will show 12.6V or more, while 12.2V represents a 50 per cent discharged battery. Start by measuring the voltage at the battery when no load is being drawn from it. These can be checked with a cheap electrical multimeter. (Right) Cranking test - a minimum 9V is needed to start a diesel engine, 10V is ideal If the starter motor fails to turn the engine quickly the most likely faults are a problem with the battery, or in the wiring between the battery and the starter motor. (Left) Checking the open circuit battery voltage - a well-charged battery will show 12.6 or more. Changing the filters and bleeding air out of the system will get you under way once more, but won’t solve contamination in the tanks – take the first available opportunity to clean them. If it still won’t start, this points to blocked fuel filters. If the engine doesn’t now start, it may benefit from being bled in the same manner further along the fuel system at the injector pump and in extreme cases by loosening the nut holding the fuel pipe at the injectors themselves. If a mixture of air and fuel bubbles out around the bleed screw continue pumping until no further air bubbles are seen and only fuel emerges, then re-tighten the bleed screw.
#Service def system engine will not start manual
Loosen the primary bleed screw – this may be on top of engine mounted fuel filter or at the injector pump – and pump the manual lever on the fuel lift pump 6-10 times. Many modern engines are described as self bleeding, but a degree of intervention is often needed. Any air in the system needs to be vented (bled) before the engine will operate properly. Air in the fuel also causes similar problems – this can enter the fuel system through two mechanisms, running out of fuel, or leaks on the suction side of the fuel pump, which will draw air into the fuel lines. While the engine may continue to run at slow speeds, eventually the filter is likely to become further clogged until the point at which complete engine failure becomes inevitable is reached. A drop of power over a period of a few minutes is a sign of partially blocked fuel filters.
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A second possibility is bacteria that live in any water in the tank and feed on the diesel, which appears to be a bigger problem with modern fuels that have a component of biofuel. This often happens as a result of a passage in rough seas that agitate sediment that normally sits on the bottom of the tank. Even if changed at the engine manufacturer’s recommended service intervals these can become blocked by debris that collects in the fuel tank. To ensure no particles of dirt – even microscopic ones – can reach the precision parts of the fuel injector pump, there should be a pair of filters in the system.