Welcome to the forum. There is a very good SIMAR website with a lot of information about the various models of Rototiller.
I will look through my collection of manuals to see what I have.
Parts for the machine, other than bearings,seals and magneto, will have to come from a scrap machine. They are very well built and reliable. Long periods of storage exposed to the weather can result in engine siezure due to rain getting down exhaust and into cylinder.