David Johnston posted:In addition to external air leaks, I think internal passage to passage leaks can also impact the operation of the whistle. You might want to take the rear cover off again and start with a new fresh gasket. Then be sure all the pins get pressed back in with even pressure to avoid any leaks, internal and external. I prefer the earlier screw on covers. Much easier to get uniform pressure.
Thanks, David! I did replace the gasket with a fresh one. The trouble with the pins is that some go back in too easily (and fall out again easily) while others require a jackhammer to re-seat. This whistle does not have threaded grooves to seat screws instead of the pins.I wish it did!