Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Easiest thing I do is lift the valve slightly and put a drop of steam cylinder oil on it, then sort of twist it back and forth as it is pushed back down into its properly seated position. If it is really bad, I will use a bit of fine lapping compound to lap it into a better seat in the valve body. Don't know if I've ever had a Jensen steam valve that didn't leak at least a drop or three during a run, but you should be able to make it so it is not leaking a jet of steam.

Hope that helps.