87 runabout gas leak from pilot adjuster

I have an 87 runabout truck camper with the HF8012P and it is burning great but I could hear a hiss and smell a small amount of has. Inspection showed that the his was coming from the pilot adjuster screw. Taking it out there is no o-ring on it and doesn't appear to take one.

Is there an o-ring I need?
Is there a seat that needs to be replaced?
Is there a cap that goes on it?

Thanks for any help