Actually, one of the members of the Stovebolt Volunteer Fire Department bought a truck with a Barton Front-mount, and included was the device you describe. Basically, it looked like a right-angle lug wrench with a collar on it. The coller fit inside the pump suction, the wrench went around the square impeller nut, and, with the pump engaged, you cranked it like staring an old car by hand. Can't remember if it was somehow geared one way or the other.
The screen you're talking about is only "soldered" into the pump by dirt and corrosion. With some judicious use of a mallet and screw driver, or a pick, you should be able to remove it.
I agree that it doesn't get mentioned later, seems like everyone agreed that it was better to be sure the electric starter circuit was in good condition, than trying to start one of these by hand!
Of course, maybe if they just built the firehouse on a hill, with the floor tilted out, they could just pop the clutch . . .
-Michael
