OK, I got it started, although it took a new battery (Li-Ion, wrong size, long story!) and a LOT of cranking. There was a lot of smoke smelling of oil and petrol then it died down and seemed to run OK. It now starts again on the stock battery. Any expert diagnosis from that? P.S. I may have over-filled it with oil as the level is right on/just over max on the dipstick.