The subject says it all, it is tight, I snugged it with my pliers, not too tight, but tight enough it ought not leak. Is there some kind of washer, gasket,  or something that is supposed to be there that isn't on mine? I haven't had this problem before, just in the last month or so.

Thanks for any help you can give.

Yeah, mine did that too a ways back.  I'm pretty sure their is a gasket that you can replace for about a buck.  I put on a plug and gasket for $8.  I ordered both, although in retrospect, I probably just needed the gasket.

I don't know if there is anything "uber special" about the O-Ring.  You might get a suitable replacement at the hardware store.

Dave wrote, "I don't know if there is anything "uber special" about the O-Ring.  You might get a suitable replacement at the hardware store."

Justin wrote, "Hardware store.Take the filler cap in, get a "not too skinny, not too fat" O-ring. Spend less than a buck."

I don't know how to quote two posts in a reply, but I do know how to copy and paste! That's the info I was looking for. In fact, I had an O-ring in the shed that seemed to fit, I could feel it squish down as I tightened it by hand. I wiped the oil off and we'll see. I hope to ride her today, we'll have to see if the rain holds out.

Thanks a lot fellows!

You can go to auto parts store an get the "O" ring.  Ask for one made of nitrile, oil and gas resistant.