I bought an Alroh 20" split rear rollers mower yesterday for $550 (on the basis of pictures only). Upon picking it up in the absence of the seller I discovered that the fuel tank is quite grimy inside which beside being a sign of some neglect might not be a big deal. More concerning is the fact that it can be rolled forward without any problem but can't be backed up to manoeuvre it easily because the the right side of the split roller locks up in reverse; the left side rolls freely both backwards and forwards. Have I bought some woes... or is it likely to be something simple? Also, the long lever clutch appears to have been replaced with a cable and some additional supports attached to the mower for holding the Alroh catcher which came with it. The serial number is 20B6272 which I am guessing means model 20B built on 6th Feb. 1972. It has a Kawasaki engine. Any preliminary comments, advice, and other useful knowledge about this model would be greatly appreciated.