heavily, but served well for most Model T usage. Many types of water pumps were available as aftermarket accessories. Ignition system The Model T engine's ignition system used a flywheel-mounted magneto to produce the current necessary to produce a spark to initiate combustion. This current was distributed by the timer (analogous to a distributor in a modern vehicle) to one of the four trembler coils, one for each cylinder. The coil stepped up the voltage and discharged it to the spark plug in the cylinder. Ignition timing was adjusted manually by using the spark advance lever mounted on the steering column, which rotated the timer, advancing or retarding the ignition timing. A certain amount of skill and experience was required to find the optimal spark timing for any speed and load. The magneto was the first Model T component to be assembled on an assembly line, and the method was copied to many other Model T production segments. The ignition system of the Fordson tractor was similar to the Model T's. Electrical System In the early years of Model T production, all engines were started with a hand crank. A battery could be used to supply ignition current for starting, since it could be difficult to hand-crank a very cold engine fast enough for the magneto to produce sufficient current. However, although all Model T's had a "BAT" (battery) position on the coil box switch and a corresponding terminal on the box. Ford did not supply or even encourage the use of a battery before 1919, when it introduced a battery-driven electric starter. Even this was not standard equipment for all models until sometime in 1926, the last year of production. Most cars sold after 1919 were equipped with this starter, which was engaged by a small round foot-operated button switch on the floor. These cars included a battery and a generator for recharging it. In keeping with the goal of reliability and simplicity, the trembler coil and magneto ignition system was retained even on cars with the starter system. When electric headlights were introduced in 1915, the magneto was upgraded to supply enough power for the lights and horn. If a Model T had an electric starter equipped, the upgraded electrical system would also be used to supply power to these items. Operation Operating the T engine was not difficult after some experience, although the learning curve was longer