Yepp, the cart was on #3. We could start that with battery power only, and use cross-bleed air to start the other three. We still only had battery power until we got one of the others started (usually the other inboard), as the accessory drive could only accomodate one (the starter) or the other (the generator). Because of the heavy electrical requirements of the mission equipment, they were 3 big generators. (I'd have to dig a manual out of a closet to put a number with "big.")
It was very difficult, but we learned it was possible to convert, in the field, a #3 engine (with the start cartridge) to a #1,2, or 4 engine (with the generator) by swapping the accessories. We were hard down in Riyadh with a bad #4, but the only spare we had in theater was a #3. As the Ops Officer, I asked why they couldn't swap the parts. They said it might be possible, but it had never been done before. Nothing like a challenge to raise the morale, right? I even pitched in getting my own hands dirty, and they only swapped two wires on the first start attempt. The engine ran, but the generator didn't. Once they got the correct wires on the correct terminals, it worked like a champ.
I'm sure you're aware the TF-33s (or at least the cores) were also used on the C-141.
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