The first step would be to remove the spark plug, lay it on the metalwork of the engine (very important) and operate the starter. Look for a good blue spark at the plug electrodes. If the plug is wet with petrol, dry it as well as you can, and operate the starter to clear unburnt fuel from the cylinders. Its also a good tip to acually heat the plug up if you can before trying again. Occasionally, even a plug that is sparking well doesn't work when its in the engine though, so a spare plug is a good move to try.
John, December 2007
