After advice from friends and forums it was time to head back and give everything a go. So armed with a new spark plug, a tin of 3-in-1 and a can of gypsy breath (easy start) I headed over to the boat yard to try getting the engine going again.
First off was a good glug of oil straight into the cylinder in case the seals had shrunk. After giving it a few cranks to give everything a nice coating I fitted the new spark plug. Then it was back to cranking away. There was definitely some improvement. It was a lot easier and after a while a nice “shhh-ti-cop” noise began to come from the carb with each turn but it still wasn’t firing.
Next I tried adding a couple of drops of fuel straight into the cylinder. After a few cranks there was a spark of life and the fly wheel turned a couple of times before dying. Enthused I tried again but nothing. Then took the spark plug out, dried it and replaced it. A few cranks and bingo. Another brief sign of life. I repeated the cycle a number of times, then the yard owner had a go. Strangely, the old spark plug seemed to work better. By now where getting three spins. Scratching our heads we checked everything to find the exhaust valve was not open. Remedying this and there was a cough a splutter and then a shuddering build up as the engine kicked into life. Once up an running and it seemed hard to conceive of a more satisfying sound!
Since this time there have been a few breakdowns due to a variety of faults including the need to clean the carburettor and not having enough fuel in the tank. It was by no means empty, but being gravity fed needs the tank to be more than half-full to operate properly.