As most engines have the ignition considerably retarded when starting, the igniter will trip later with the lever in the “start” position than when in the “running” position. Never fail to retard spark when starting nor forget to advance it when engine is up to speed.
The actual advance given to an engine depends on the character of the fuel and on the speed.
An engine is said to have an advance of 10°, if the crank lacks 10° of having made the inner dead center at the time of ignition.
The most economical point of ignition is easily determined when the engine is running on a steady load, by varying the point of ignition and noting the position assumed by the governor.
(88) Operation of the Make and Break Igniter.
To keep the igniter in order, and to obtain the best results with the least trouble, the following hints should be observed:
(1) Clean the igniter frequently, and remove all deposits of oil and carbon. For cleaning, the igniter must be removed from the cylinder, care being taken to avoid injury to the packing or gasket. Graphite dusted on the gasket will prevent it from sticking to either the igniter or cylinder.
(2) If the contact points are rough, pitted, or covered with a carbon deposit, the scale should be removed, and the points smoothed down with a fine file, taking care that the two faces are filed parallel with one another.
(3) Insulating washers and tubes should be removed and washed in gasoline. The hole through which the igniter rod passes should be scraped free from any deposit for much trouble can be caused by a tight working shaft.
(4) Examine the hole or bushing through which operating spindle passes, for wear. A worn spindle or bushing may cause a serious loss of compression; replace worn bushing at once.