Good one, Tom!
Reminds me of my first TR3A, where one of the very first things I did was to substitute the points, condenser, cap, wires and coil from Dad's running TR3A. Spent two days standing ankle-deep in snow trying to get it started. Checked everything we could think of: timing, valve lash and so on. Cleaned the carbs and fed them directly from a gallon can of fresh gasoline (to bypass the crud in the tank) Lots of starting fluid and backfires (lost my eye lashes too). We even managed to run down the battery on my 65 Olds with the engine still running! (Very strange, it was idling fine but died when I put it in gear.) All this was out in the middle of nowhere, without so much as a pay phone within walking distance, (and long before the days of cell phones). There had been one or two cars pass by earlier in the day, but nothing for hours when the Olds died.
After coaxing the Olds back into life (whew!), we pulled the TR on a rope back to my buddy's trailer, some 40 miles away. Illegal as all get-out, so we kept to the back roads and of course I was the one that got to pilot the TR with ice cold air blowing up my pants leg through the holes in the floor. Fortunately the brakes still worked.
Next day the battle resumed with the bright idea that maybe it was just too cold to run; so we linked up the heater hoses from the Olds to circulate hot water through the TR block. Didn't seem very hot, so I slid some cardboard down in front of the Olds' radiator (which I frequently did in winter anyway, to get more heat). Another long, frustrating day, the TR would pop and puff and chug like it wanted to run but just never would light off. Finally getting dark and too cold to work, I pulled the radiator cap off the Olds and promptly got a shower of boiling glycol up my jacket sleeve and over my head.
Later, while treating the burns, it finally dawned on me what the problem was. Can you guess?