WOW. Your mower certainly has not seen much work if it still has the plug cover ...
If your looking for a catcher I am selling one on eBay now (New old stock).
Are you sure you are getting spark? You note in your first post that you seem to be getting good spark - Bright blue? These machines give a very bright BIG spark so if your not getting that change the plugs. Do you have compression? Maybe remove the decompressor valves and test them - attach a length of clean fuel line to the outlet and suck. If they close up they're OK.
They never were a particularly reliable machine.
Pete
