XJ900 RK petcock loose outlet

My petcock seems to have at least one problem: when the engine is not running, if I unplug the fuel line from the petcock, it doesn't stop flowing immediately, it drips for several seconds and it makes a big mess on the floor. I think the spring under the diaphragm may be a bit weak because the diaphragm itself looks ok to me. I was said the best cure could be to put a thin washer under that spring to improve the seal.

I also think about rebuilding it but there could be another problem, you guys will tell me: the fuel outlet is a bit loose , I don't know if it is normal or not. I can turn it a bit left or right, until the fork-like part (red arrow) hit the stopper. It looks like it is designed to turn a bit, right ? I won't buy parts to rebuild it if it is actually falling apart...

 

The one on my Virago 750 turns, too. It doesn't leak, so I'm thinking the swivel is by design.

The leaking when unplugged may be because some cleaning is needed and varnish and other gunk is making it stick a bit. A new O-ring for the plunger may also be indicated.

 

I opened it and didn<t notice any varnish. As for the o-ring, I will give it another look.