'77 Winnebago Brave, Dodge 440 engine
A727 transmission
Refused to start.
She Who Must Be Obeyed and I were in Nevada (Wendover). We had been there two days. I started the Whiny Beggar every morning, because she was new (to us), and I didn't know just how good the inverter/converter system was. No problems. She started up.
When we were ready to leave, I pulled up to the office to pick up a minor cosmetic part. When I came back, she refused to start. So, I went back in the store and purchased a can of starting fluid. After half a can, she finally started.
We wended our way across I-80 to Salt Lake City. No problems (other than the winds I was fighting). The next morning, she started up with no problem.
We finally made it home (Ogden, UT), and used her a time or two more, but with some problem in getting her started. The starter would groan, but eventually kick her.
Eventually, it turned out that the problem was the starter motor. The one in her was original. (We had to take it out with a hammer. Once the bolts were out, the motor wouldn't even budge.)
In the meantime, I had replaced the starter relay, the voltage regulator, and various sundry other parts.
What fooled me is that she WOULD start on occasion. Just sometimes she wouldn't, and it didn't seem to matter what the temperture was, the humidity, etc.