I stumbled on this while climbing out of a YouTube rabbit hole and thought it might have a receptive audience here. The plane belongs to a vintage motorcycle museum in North Carolina.

Safety-minded viewers will cringe at the owner's hand-propping technique, but he's already been eviscerated for it in the comments. His explanation is this:
"Most airplane engines engines have several more cylinders and/or far better than a 315 degree firing order. Found that we had to get it past two compression strokes to get it to fire. One pull simply wouldn’t do it. Admittedly not the best solution, but appeared to be the only solution."
Spoiler: they make no attempt to fly the plane in this video, but do taxi it briefly at the end.