G'day Arthur, yes, the magneto is underneath the engine on a power torque engine. It should not require a special tool to remove it, as it is just 2 12 mm bolts. I normally use a 12mm deep socket, I think the later models are 11mm.
thanks tomo the model i have has a collar with a recess drilled into it so that you need a curved tool with a short 6mm shaft to fit the recess im sure ive seen a similar tool somwhere but just cant remember where
i know ive seen the tool looks like a scimitar with a half inch dowell at the end it wraps oround output shaft hooks in2 the collar and has about a 5" handle