It had run during an earlier test.
The oil pressure was acceptable at that time.
The old man suspected a loose terminal or deteriorating connection in the electrical system.
There was no note about a seized crankshaft.
No description of catastrophic internal damage.
No report of metal fragments in the oil.
No overheating incident.
No sudden mechanical failure.
The boy knew that a machine could develop serious problems between one inspection and another.
His teacher reminded him of that.
But the grandfather's notes did not support the dealer's confident description of an engine destroyed beyond repair.
Then he found one sentence circled in red pencil.
Check ignition feed before condemning engine.
The boy stared.
He read it again.
Then again.
For several seconds, he could almost hear the old man's voice.
Don't guess when you can test.
He copied the diagram onto clean paper.
Labeled the connections.
Then took it to the retired farmer.
They sat at the older man's kitchen table.
The farmer studied the drawing through reading glasses.
Then nodded.
"That's the modified ignition feed."
The boy leaned closer.
"Could it stop the engine from starting?"
"Yes."
"Even if everything inside the engine was good?"
"Yes."
The farmer looked toward him.
"But remember, one possible electrical fault doesn't prove there aren't other problems."
The boy nodded.
"I know."
The older man smiled.
"Good."
He tapped the notebook.
"Your grandpa wanted to test the electrical side first."
The boy considered.
Then asked.
"Do you think the dealer did that?"
The farmer's expression darkened.
"I don't know."
He looked toward the boy.
"And neither do you."
The child lowered his eyes.
The older man continued.
"Don't accuse somebody just because you don't like their answer."
The boy nodded.
Then the farmer added.
"But don't stop asking for evidence."
The boy looked up.
For a moment, they smiled at each other.
Then the older farmer opened a drawer and removed an old service manual.
Its pages were yellowed.
Several corners were bent.
He placed it beside the notebook.
"Your grandfather gave me this years ago."
The boy stared.
The cover showed an older John Deere tractor.
The farmer nodded toward it.
"Take a look."
The boy carefully opened the book.
For the next two hours, they studied diagrams.
Ignition components.
Fuel delivery.
Engine controls.
And the importance of conducting tests safely.