When you checked the condition of the rotor arm, did you not also check the condition of the dizzy cap for the same wear? It's by no means certain (to us, anyway) that they've been on the vehicle for the same amount of time but it only requires a rudimentary check of the posts for signs of excessive tracking, the body for hairline cracks or chips (usually evidenced by moisture on the inside of the dizzy cap).gazzafield wrote:...What I can say is that since replacing the rotor arm it has started up again before giving up the ghost completely. It wouldn't start up at all after conking out before the rotor arm was changed, which I find odd.
So at least I now know it's the ignition "side" of things. I was thinking of possibly working back from the plugs. So the next thing would be the dizzy cap, then coil.
I would probably have changed the rotor arm and dizzy cap as a pair.
I've never seen a coil fail. That doesn't mean that they don't but it's rare. I would take the coil off the wing, and break it down for a good clean, also the mounting point on the wing and that the coil re-battens itself down nice and firmly.