Hi everyone,been a while since I posted last.My neighbor has a 62 Ford 4000 industrial backhoe and it won't start.We narrowed it down to fuel line or filters.The problem is that there doesn't seem to be a shut off valve.There is some kind of fitting on the bottom of the tank that has a hex shaped thing but cannot get a wrench on it because it is recessed into a housing.It located where I would think a shut off valve should be.If it is a shut off valve,how does it work?And also is there a filter in the inlet port of the carb like our N tractors have?As always,any help is much appreciated. Mahlon