The plug certainly can fail - and that is the most likely cause of the problem. Change that first. Put a teaspoon of fuel into the plug hole before replacing the plug.
If it fires, the problem is in the carburettor.
If it does not, remove the plug and put your thumb over the hole and pull the rope. The compression should easily blow your thumb off the hole. If it does not, it's possible that a valve is stuck, bujt this usually only occurs if the engine has been standing for years.
You may also have a blown head gasket, and/or a weak coil. Head gasket is cheap, ignition coil is not. Testing the coil properly requires expensive test equipment.
There are no points. Hpoe this helps - there is no service manual as such for this machine.
phil_saunders(a)bigfoot.com
Phil Saunders, August 2009
