I've been given an old mower, quattro 40. I've got all the control wires freed up and petrol going to the engine but it won't start. The spark plug seems to have oil on it. It's been sat in a shed for about 4 years without running.

Tim Brown, February 2013

could b seized or broken oil ring on piston

gerard, February 2013

One of the biggest problems with this type of mower is when people tip them up to clean the blade or the underside of the mower deck. It allows residual oil in the engine to migrate past the piston in to the combustion chamber and it oils everything up. If you tip it sideways the oil runs down the inlet manifold and ends up in the foam air filter which then chokes the engine.
Only ever tip a mower up by lifting its front wheels, that way the oil in the engine stays where it is.
Remove the air filter and wash it in paraffin or petrol to get rid of the oil, then dry it. Remove the plug and clean it. place a rag over the plug hole and hand crank the engine to get as much oil as you can out of the cylinder head.
If you have got an aerosol of Bradex Easystart (from Halfords etc), spray some into the inlet manifold and away you go.
Ps You can come and test it on my lawn any time!

GB in Wales, February 2013