What the click’s up?
QWhen I turn the key to start the engine I get just a clicking noise for perhaps 10 to 20 attempts, then it just suddenly starts. I have purchased a new starter motor but that has not fixed the problem. TONY REPLIES... At the end of the smaller cylinder on top of the starter motor, you should see two nut type terminals, one with more than one wire on it, and one single small blade or small nut terminal with just one wire on it. This terminal ‘turns the starter on’.
Get a length of cable (say household three-core mains flex), fit a crocodile clip to one end (use all three cores), strip and twist the other ends together. Clip the cable to the starter battery positive taking care not to touch the other end to anything metal. Now firmly push the bare end against the small solenoid terminal with just a single wire on it.
If it ‘clicks’ as before, then the problem is within the starter (unlikely as it is new), loose or dirty main battery connections, faulty master switch, or something odd on the large negative (earth) wiring for the engine.
AIf it works every time then the problem is with the supply to that single wire terminal. Look along the main wiring harness from engine to instrument panel and you may find at least one large multi-way plug and socket. Manipulate this: if the fault clears, make sure all its connections are clean and tight.
If that doesn’t work, then I would suspect undersized cables or loose/ dirty terminals between the batteries and ignition switch or between the ignition switch and starter, or faulty ignition switch. However, the fact the heater and fridge are okay for 24 hours suggests that the alternator is probably all right.
I suspect your batteries are badly sulphated (ends of batteries bowed out are a sign) so they are down to a fraction of original capacity. One or more may also have faulty cells (which will normally gas more when charging and be drier than good cells).
Without hydrometer readings for each cell plus the voltage reading it’s hard to be certain, but I suspect a new set of batteries has a better than 75 percent chance of solving the problem.
It’s also worth undertaking a power audit of your boat and charging calculations: there’s a sample in the maintenance notes at tb-training.co.uk. I suspect just three x 110 Ah batteries running a fridge and Eberspächer for more than 24 hours without recharging is optimistic and may lead to reduced battery life.