I'm for checking the pump setting.

Stupid stuff like that tends to bite ya.

Once, when selling a lawn mower which had been utterly reliable for about 8 years, it wouldn't start. Quite embarassing really. In the process of jumping it off, realized the battery wasn't dead. Apparently, you need to press the brake while starting it. I'd been doing it without thinking about it for years, then forgot all about it.

Another time, I had been driving a parts van for several days, as an appliance technician. Then it just wouldn't start. I called up the boss, and he tells me to mash the brake while I turn the key. Bingo.