For downloadable manuals, try Manage My Home. You will probably have to register, but it is free. The site will allow you to download PDF versions of just about any Sears product. I did not see a manual for the model number you specified, but there is a 917.273050 and 917.273051 which "should" be close. Look at the manuals and see if either is a close match, I would think they will be very close. A quick look on my part showed a slight engine difference (CV20 vs. CV20S), but I suspect the tractor itself is identical. You can always use the part direct site for final verification before ordering anything.
Just an FYI to everyone reading this, you can search the Manage My Home site using "short" numbers (i.e. 917.27305 for instance) to see what it has in that numerical series.