Physically, the cover from the p42 will fit the farmsaw, but it will not work without modifications. The farmsaw has a different engagement cog than the p42. You would have to change the flywheel on the farmsaw to that of the p42 to get it to engage when you pull on the cord. If you change the flywheel you will need the electronic module from the p42 as well because the p42 used the phelon ignition(black), while the farmsaw used the prestolite module(blue). If you do not have the black module and wish to use your farmsaw prestolite module, you could try to hunt up a flywheel from the P38 which used the prestolite module and has the right engagement style for the P42 recoil assembly. Unless you have all the parts from the P42 or can get a parts saw cheap, it would be easier to fix you farmsaw starter recoil. Have you checked ebay? There have been several farmsaws go for sale this year that would make a good parts saw. There is one on currently, but unfortunately, does not have the recoil that you need. Have you checked various dealers around your area to see if they have any old parts saws? What do you need to fix your starter? I can keep my eye out to see what I can find in my tours here if you would like.