Incident
During an engine run-up, a fire erupted in the engine compartment. The event prompted an investigation into the cause of the fire.
Investigation Findings
Examination of the engine revealed that seven of the eight nuts securing the exhaust manifold to the cylinders were missing. The only nut present was loose but retained the number 1 cylinder exhaust tube. The number 2 cylinder exhaust tube, though not secured, remained in place. The number 3 and 4 cylinder exhaust tubes were unrestrained and had dropped down, allowing exhaust gases to escape from the manifold.
Heat damage was notably worse along the left side of the engine compared to the right side. The fuel pump fuel line sustained burn damage sufficient to allow fuel under pressure to escape into the engine compartment, contributing to the fire.