I'd sure like to know what kind of clutch you have on that saw, it sure doesn't look like a P42 original.
The carb and magneto are still available if you need them. Make sure the kill-switch wire is OK. Try putting both carb screws in all the way and then backing them out 1 turn each. It's a good place to start with those Walbros. They are simple saws that love to start and run. If they don't work properly then usually the carb needs to be cleaned and the metering lever set, or the magneto needs to be replaced. The first thing I would try though is a brand new spark plug. I've been led down the garden path too many times by using two crappy ones in a row, so now I always start with a new plug when troubleshooting. Nice, fresh gas always helps, too.