I have a 1971 55HP Chrysler, model 557HC serial 3188. When I removed top plate the diaphragm had a gasket on top and bottom. My parts number A84747 says diaphragm with gasket and the other part no: 84760 is gasket. Both numbers in my manual point to specific part. So my understanding is the diaphragm come with a gasket attached. Is this correct? The other part number is just a gasket. I ordered the parts and was sent a diaphragm (without gasket) and a gasket. Put on the fuel pump and it wont start. The diaphragm did not come with a gasket attached. just the diaphragm. So there is not a gasket on top and bottom. Just one gasket. Help
