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I have a pair of 50H (full name F50HETL), one is 2017, other 2023. The older engine (serial no. 6C1 - 1074688) has developed an electrical fault and will now not start. I am running out of ideas, and so posting on here to see if anyone can suggest what I should do next or something I may have missed. I am fairly competent with the fuel side of my engines, but do not know much at all about the electrical side of things. Apologies if the explanations below do not use the correct language!
Symptoms: When I turn the key to start, there is a single click. Nothing else. The voltage on the digitial display drops about 0.3v when I turn the key, then returns to 12.2v. Tilt/trim still works fine. The other engine on the boat runs from the same batteries and starts no problem
Diagnosis attempts:
I have tested the batteries, they are fully charged. I have connected a spare battery directly to the engine, this also doesn't work. So to me this would suggest that the battery cables to the engine are OK. I've checked the connections all the way from the batteries, through the isolators to the engine and everything is tight and clean.
I have swapped the starter motor and the relay(?) (small black box below the starter with two M6 terminals and two small wires coming out the bottom) from a spare identical engine I have in storage. I bench tested the relay I took off the engine and it reads fine for resistance, and clicks when I connect the two small wires to a battery. I tried bench testing the starter motor I took off the engine when I put the spare one on, but not sure if I was doing it right. I put the negative cable from battery onto the starter body, and positive onto the large terminal on the starter. Nothing. Does it need a signal from the ignition too? What are the chances of two starter motors both being bad?
Next step will be to try the starter motor from working engine on the boat. And possibly the relay too.
I am also considering swapping the wiring harness from my spare engine onto the dead one. If the neutral safety switch was faulty, would this stop the relay from clicking? Is there any other sensors that would still allow the click, but wouldn't let the engine start?
Any help would be most welcome. TIA
Symptoms: When I turn the key to start, there is a single click. Nothing else. The voltage on the digitial display drops about 0.3v when I turn the key, then returns to 12.2v. Tilt/trim still works fine. The other engine on the boat runs from the same batteries and starts no problem
Diagnosis attempts:
I have tested the batteries, they are fully charged. I have connected a spare battery directly to the engine, this also doesn't work. So to me this would suggest that the battery cables to the engine are OK. I've checked the connections all the way from the batteries, through the isolators to the engine and everything is tight and clean.
I have swapped the starter motor and the relay(?) (small black box below the starter with two M6 terminals and two small wires coming out the bottom) from a spare identical engine I have in storage. I bench tested the relay I took off the engine and it reads fine for resistance, and clicks when I connect the two small wires to a battery. I tried bench testing the starter motor I took off the engine when I put the spare one on, but not sure if I was doing it right. I put the negative cable from battery onto the starter body, and positive onto the large terminal on the starter. Nothing. Does it need a signal from the ignition too? What are the chances of two starter motors both being bad?
Next step will be to try the starter motor from working engine on the boat. And possibly the relay too.
I am also considering swapping the wiring harness from my spare engine onto the dead one. If the neutral safety switch was faulty, would this stop the relay from clicking? Is there any other sensors that would still allow the click, but wouldn't let the engine start?
Any help would be most welcome. TIA
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