Remove cowling and see if there is a coil mounted OUTSIDE the flywheel. If so, check if there are wires leading under the flywheel. If there are, the engine has points. If not, it's solid state. Either way, replace the coil with a solid state module, cut the wires (there will be - one to coil & one to stop device) to the points & join the stop wire to the small terminal on the new coil.
Alternatively, if the coil is OK and the points are worn/corroded, simply buy a conversion kit & attach it to the stop wire.
If the COIL is under the flywheel, drop me a line & I'll advise.
phil_saunders(a)bigfoot.com
Phil Saunders
April 2010