The next attempt came at eleven fourteen. The diesel turned, coughed twice, then caught. For several wonderful seconds the engine beat unevenly but unmistakably under its own power. A cheer lifted from the crowd. Martha kept her hands steady and watched the instruments, refusing to confuse the noise of applause with evidence of a stable idle. The engine shuddered, slowed, and died before the fifth second. The cheer broke off as quickly as it had begun. In the sudden quiet she could hear the tick of cooling metal and a man muttering that it was never going to make the deadline.
She climbed down without looking at Calvin. June was already beside the test section, working the hand primer gently and studying the fuel. A line of tiny bubbles appeared, disappeared, and appeared again. Martha looked over June's shoulder. The fuel had seemed clear while they primed it by hand, but the bubbles returned after the engine drew on its own. Martha initially dismissed them as air left by the filter change, and then something in June's expression made her stop.
"What?" Martha asked.
"We cleared it before the last attempt," June answered. "I watched. Then it ran, stopped, and the bubbles came back."
Martha checked the connection she had inspected twice. It looked sound. That made her want to defend her earlier conclusion, a reflex she knew too well. For one unflattering second she understood why some older mechanics disliked apprentices who noticed things. The apprentice was asking her to return to a place she had already marked finished. The deadline was moving. The audience was waiting. Going backward felt like losing time.
"It's probably leftover air," Martha said.
June held her gaze. "Then why does it keep coming back when the engine pulls fuel?"
Martha had no evidence-based answer. She looked at the clock over the office door and saw eleven sixteen. Forty-four minutes. Enough time to be wrong once more, maybe not enough to be wrong twice. She took a breath and heard her father's voice again: if a younger person sees what you missed, you have received a gift, not an insult. Martha crouched beside the line. "Show me exactly what you saw," she said.
June did. She traced the flow, described the difference between hand priming and suction under engine operation, and pointed toward a fitting partly concealed behind a bracket. Martha followed the direction of her finger. Dust sat undisturbed around its base, which made the joint appear sound at a glance. A dry connection was not necessarily an airtight one. Air could enter a suction line without leaving the visible wet stain that people expected from a fuel leak. Martha had checked the fitting visually but had not yet proved it would hold under the conditions that mattered.
They isolated the suspected section and tested it. The joint failed to hold a proper seal. When they examined it more closely, they found a flattened seal and a short split in an aged hose end tucked behind its clamp. The flaw was small. Its effect was not. Every time the engine drew fuel, the damaged joint admitted enough air to interrupt the flow. The engine would cough, perhaps start, and then starve. The problem was almost embarrassingly ordinary. A bad crimp, a neglected filter, a failing hose, and one hidden suction leak had become a verdict that an entire combine was worthless.