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

Come to think of it...... I had a similar problem with a steam locomotive I made. It initially had a steam globe valve
that had a hole for the needle valve seat that was 1/8". The engine would prime badly when I opened this valve . I later
Remade a globe valve with a 1/16"needle valve seat and the problem was solved. I noticed today that if I opened the
whistle valve a very small amount the whistle worked better. Is my boiler reacting to the sudden pressure drop by boiling over or ebullation? (Not sure of spelling)