There are many places that one could find a Rototiller for purchase. One popular place where you will be able to get advice on the best Rototiller for you would be Lowes.
a rototiller
call Sears warehouse and you can order one. Also check online as they may have it there.
http://www.searspartsdirect.com/partsdirect/index.action
I did not find a manual but it seems that vendor number belongs to Husqvarna.
you can find a users manual or troubleshooting guide for the Homelite rototiller model HTC 12, on the Homelite website. Click on the Service and Support tab and then on Operators Manuals.
a rototiller
model 5 C Ser # D001943
Google, plain out and simple.
You can find a manual for your Rally rear tine self perpelled Rototiller model RYX820K, manufactured by American Yard machines, on the American Yard machines website. You will find manuals for all of their products on the website.
You should be able to go to the website and find your tiller in the parts search area
seaweed is
You will simply need to research with google, bing, wiki, eBay etc to locate one. try searching for both Wizard and Western Auto.