I electrically disconnected my lanyard switch because it's broken, the engine ignition wiring (purple wire) was routed through it but it was broken in a way which made it have high electrical resistance which caused a voltage drop to the ignition coil.
When I bought the boat I was given a video by the previous owner showing a guy from a marina demonstrating the engine start procedure.. He turned the ignition on then flicked an auxilliary switch on the dash before turning the key to crank it then flicked the auxilliary switch back to off. At first I thought someone must've fitted some type of basic immobiliser but after checking the wiring I found the auxilliary switch simply bypassed the igniton key! The marina guy was showing the po how to bypass the ignition and lanyard kill switch using the auxilliary switch when starting the engine then flicking the auxilliary switch back to off again so the lanyard kill would work and the engine would switch off when you turned the ignition off.
There was no immobiliser, I realised that it wouldn't start unless the auxilliary switch was used because before the alternator was charging the voltage drop to the coil saw the coil getting too low voltage to create strong enough sparks for the engine to run, the only reason it continued to run with the auxilliary switch turned off after starting the engine was because with the engine running battery voltage was high enough to allow the coil to work good enough despite the voltage drop.
After bypassing the lanyard kill switch I fitted an ignition relay on the engine itself, so power to the ignition coil is switched by the relay and the relay is switched by the purple wire from the dash/helm. With this setup instead of all the power for the coil running from the battery up to the helm and back to the coil it runs straight from the battery to the coil, there's only the very small electrical current needed to switch the relay running through the ignition wiring/helm... The small current needed to switch the relay doesn't cause a voltage drop so I could reconnect the lanyard kill switch and it'd switch the relay and as long as the relay switeches the coil gets full battery voltage anyway. But the best fix would be to keep the relay setup, fix the lanyard kill switch, reconnect the lanyard kill switch and maybe disconnect the auxilliary switch ignition bypass.
I have so far left the auxilliary switch wired as an ignition bypass mostly because I never got around to disconnecting it... but also because I think it could be an advantage if I ever accidentally dropped the ignition key over the side. Supposed to need a key to make the engine run, an anti-theft device, but anyone who knows a bit about what they're doing could still nick the boat without the key just by connecting a couple of wires on the engine anyway and a thief wouldn't know that the auxilliary switch is wired as an ignition bypass. If a thief knew what they were doing they could start and use the boat without a key by joining a few wires on the engine to make the ignition then touch a couple of wires together to crank and start it, if they didn't know what they were doing then even if they knew about the auxilliary switch bypass they couldn't start the engine because they couldn't crank it without a key.
When there's a few adults on the boat there probably isn't a big safety advantage to using a kill lanyard because if the driver fell overboard the other people could take over the driving and pick them up. But I was once on the boat by myself doing around 30knots, hit a wave and found myself feet off the floor floating in mid air just holding the steering wheel lol... The lanyard kill would've been a big plus if I'd fallen overboard instead of just having a feet off the floor moment when I was alone on the boat.
Jinxed it , damn thing crapped out right at my gate .......no spark 
