I have a 1962 2000 Industrial Gasser 134 cu in. with the screw type fuel cutoff under the tank. It was froze, so I ordered a 311292 as an OEM replacement. It is leaking right out of the box around the valve stem threads when valve is open, although it seems to be delivering fuel OK. It seems to seal and not leak when the valve is closed. From the product reviews, these shutoff valves seem to frequently leak right out of the box. Can the threaded stem be pulled out to try and reseal it (packing? O-ring?) or is the solution just keep buying shutoff valves until I get a good one?