ORIGINAL: Clean
Bwaaaa
Bweee
Burppp
Blubber
Blubber
I can recall when I first was told that a Fox burps. It was only fifteen years ago; and prior to that point I'd already been flying Fox engines regularly for about 25-30 years. Before that, fellow CL folk I met used them almost as far back as I have memories of the hobby. I didn't immediately understand all of the pissing & moaning that was aimed at this symptom.
(After I finally looked past the homeliness of Fox products, and bought some, I bought many more. Of a minimum 12 of them I've owned, and five or six I still own, not one ever shed a con rod. " That part is bullet proof",
Robbie says. George Aldrich denied ever having been aware of any such burping problem. I ran into a pronounced variety of it exactly once, personally. In the years since having first heard the "burping" complained about, I have heard Foxes do it.
And OS Maxes and McCoy red heads also. It's just part of the "normal" sound (to me) of a many old engines running a 4-2-4! Nothing to get excited about at all.)