bought what I believe is a rochester c carburetor. Top plate is thicker and fits the bolt pattern on my 235 better than the other rochester I have. The only problem I have is I'm missing a screw that goes in the top plate. It is a 12-28 about 7/8 of an inch long. I haven't been able to locate one of these anywhere, tried auto parts stores, hardware stores, fastenal, etc. Anyone have any other ideas that I haven't tried?