Rich, you have worked wonders getting that Empire running. I myself had a B-42, but could never get it to run...sold it on. Yours is a jewel. If your whistle top is still loose, smear some CA (super glue) on the male base and press the top over it...let dry and it won't rattle loose again.
Best of luck with it and your whole Empire collection...a beautiful set of engines and accessories.
Rog