230. If an auxiliary diesel engine starts firing but does not come up to normal speed, without load or under a small load, one cause may be __________.

A clogged fuel filter restricts fuel flow, preventing the engine from reaching normal speed despite firing. Diesel engine speed depends on adequate fuel quantity and pressure; a clogged filter reduces fuel delivery, limiting acceleration even under light load. This symptom—starting but failing to reach normal speed with minimal load—is characteristic of a fuel flow restriction, specifically a clogged fuel filter.