Engine refuses to start – electrical failure
It is easy to diagnose electrical failure as the reason for a refusal from the engine, because one of four things happens when the key is turned. The first is that the engine whips over with enthusiasm but shows no interest whatever in starting; the second is that absolutely nothing happens at all. The third is the sad sound of a battery without enough life left in it to turn the engine fast enough; the final symptom is an irritating clicking noise.
• Engine turns but does not fire
This may well be a fuel problem, but before considering bleeding the fuel line (see page 33) it is well worth checking that the ‘stop’ system is not activated. If the engine is stopped by pulling a toggle, make sure that this has been returned to the ‘run’ position, i.e. shoved back in. This toggle works by shutting down the injector pump and, if manually operated, is not really an electrical issue. However, on many modern diesels the same job is done via an electrical solenoid activated by turning the ignition key. If the engine won’t start, make sure this arrangement has not been compromised. To understand how it works, watch the various tiny levers and connections in the vicinity of the injector pump when the ‘stop’ is being activated. You may well see what happens. If the electrics fail to activate the stop switch, it may ‘fail dangerous’, leaving the injector pump permanently shut down, a state which you can probably over-ride by pulling out a clevis pin or unfastening a nut. As with much of seamanship, forewarned is fore-armed. There may not be time to experiment when the rocks are looming.
• Nothing happens
Unless the batteries have all taken a serious beating from a short-circuit, it is unlikely that the whole supply will be so flat as to fail to make some sort of show of turning the engine. If total silence meets the start button and the yacht doesn’t have a bank of dials reading out the voltage of each battery, it is time to get out the multimeter. Every modern skipper needs to understand the basics of using a multimeter. A workable one should not cost no more than a round of drinks. It measures current (amps), resistance (ohms) and, most importantly in this instance, it will also indicate voltage. Go to the battery box and decide which battery is supposed to be starting the engine. Dial up ‘Volts DC’ (Direct Current) on the meter, choose 20 volts from the selection, place the red probe on the positive terminal and the black one on the negative and see what the numbers say. A charged, healthy 12-volt battery at rest will usually read about 12.5 volts and 12.0 should start a happy engine. Even if it is down to ‘11-point-something’ it will usually still turn it over and might even do the trick. A 24-volt system works ‘pro rata’. When nothing is happening and the battery has enough volts to do the job, then either a bad connection is to blame, or something untoward has happened to the vessel’s switching arrangements.
If the engine start battery has its own switch, is it on? If it is, inspect all the connections between the starter motor and the battery. In a case of total failure, the problem is more likely to be in a small wire leading from the switch to a relay or solenoid than one of the big ones delivering the main punch, so examine these as well, even if you don’t understand what they all do.
Boats have different wiring systems and varying methods of connecting the battery to the starter motor, so it is impossible to generalise. A trained eye can read the wiring diagram supplied by the engine manufacturer, but for the average skipper this may prove too big a challenge. However, a wire hanging off is a wire hanging off, and it might just be the one you’re looking for! The impetus of this section is to encourage a seamanlike, systematic search for such a problem. To remake connections, the ship should carry a good supply of electrical terminals – ‘spades’ and rings of assorted sizes – as well as insulating tape, spare wire of varying gauges, cutters and some means of crimping a terminal. Ideally this will be a purpose-designed crimper, but a small pair of mole grips (vise grips) will serve. None of these items is expensive.
36 | MANUAL OF SEAMANSHIP
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