Causes for Misfiring at Lower Speeds
Poor engine operation at low speeds is a common complaint among operators of motor fire apparatus and the usual cause lies in the carburetion system, though the exact location will differ. Sometimes an air leak throws the carburetor out of adjustment so that an insufficient amount of gas is present in the mixture. On the other hand, when the magneto has weakened magnets and the spark gaps of the plugs are a little wide the combination produces low speed missing almost every time. With a battery system the carburetion system should first be inspected and if that fails to disclose the cause, the ignition system should be tackled next.