“Does it often act up that way?” Jim Nestor wanted to know.

“Not very often,” said Jerry. “We’ve got it adjusted pretty fine. I can’t see what’s the matter. There’s a good spark, and there’s gasoline in the carburetor, for I tested the drain cock. Yet there doesn’t seem to be an explosion.”

Once more he threw in the switch, and turned the flywheel. There was a buzz as the coil vibrated, showing that the electrical connections were good, but no explosion followed.

“Ned, you try,” suggested Jerry. “Maybe I’m the hoodoo.”

Ned stepped in front of the motor. But, before he attempted to turn the flywheel he gravely tied a knot in his watch chain.

“What’s that for?” asked Jim Nestor. “Afraid you’ll break the links?”

“No, it’s to break the hoodoo,” answered Ned. “You know there are so many things that can happen to a gasoline motor that no one can number them. Lots of times a little thing like sprinkling talcum powder on the cylinder head, or giving the timer a gum drop, will make her start when nothing else will. I’m just trying the watch chain as an experiment,” and he grinned broadly.

But it was of no avail, and the more Ned labored at turning over the flywheel, the more the motor seemed to balk.

“I give up!” exclaimed the merchant’s son. “It’s your turn, Bob.”

The stout lad gravely took out a bit of court plaster, and pasted it on the magnet of the dynamo.