TROUBLESHOOTING THE GAS ENGINE. WITH STAN READ


| May/June 1966



30-60 Hart Parr Tractor

Courtesy of Mr. Emil Christenson, Conrad, Montana 59425

Mr. Emil Christenson

Rte. 2, Gunnison, Colorado 81230

If your gas engine has electrical ignition but does not use a spark plug it probably uses a hammerbreak igniter. This igniter is used in conjunction with a battery and simple induction coil or with a low-voltage magneto. It has been said that the igniter system is mechanically complicated and electrically simple while the high-tension spark plug type system is mechanically simple and electrically complicated.

Because of its mechanical complications the hammerbreak igniter is limited to slower speed engines, as it begins to malfunction at speeds greater than about 750 RPM.

The hammerbreak igniter (see Fig. 1) consists of a cast iron or brass body, a, which bolts to the engine head or cylinder side so that the breaker points extend into the combustion chamber. One of the points, b, is stationary and insulated from the body with mica or porcelain and extends through the body to the outside battery or magneto connection, d. The other point, c, is movable and fastened to a shaft, e, which also passes through the body. In operation a push rod on the engine pushes against the lever, f, which transmits a twisting motion to shaft, e, through the spring, i. This holds the points, b, and c, closed so that current from the battery flows.

As the push rod continues its travel it releases, f, which strikes lever, g, which is part of shaft. This hammer-like blow causes the points to separate suddenly causing an arc which ignites the gas mixture in the engine.

Using a battery, one terminal is hooked to ground (the frame of the engine) and the other is hooked to one terminal of the induction coil. A wire connects the second terminal of the coil to the igniter insulated terminal.