A Battery Eliminator for an Economy

HP Economy Engines

Content Tools

8204 Gordon Lane, Hermitage, Tennessee 37076

After building the magneto for a Fairbanks Morse (published in December 1992 issue), I acquired a 5 HP Economy with a low tension igniter on it for the ignition.

When the engine restoration was completed, it was set up to run on a battery and coil.

At one of the shows, I recalled seeing an engine running on a low tension magneto driven from the flywheel. Wanting to duplicate this principal, I recalled some years back that I had experimented, using an automotive heater motor for a generator.

With a trip to the local parts store, I asked for a 12 volt heater motor with a 5/16 inch single shaft, permanent magnets in the fields, reversible with an insulated circuit. He came up with a Bravo U208919.

After racing home and hooking up the motor in a drill, my son cranked the engine while I held the drill and motor. Bingo! I hit pay dirt. Now, to fine tune the project.

The 5 HP Economy has 28' flywheels. After making some voltage to speed measurements, a 2' rubber wheel from a roller wheel castor was selected to drive the motor. This would put out the necessary voltage at low speeds.

The mounting bracket was made at an angle to the flywheel to conserve space. The rubber wheel was turned down to 1 inches to give a wider surface for better friction.

For a coil, several were tried. A coil in a 6 volt Ford starter relay worked best.

Some linkage was hooked up from the push rod to the heater motor. This will hold the motor away from the flywheel, releasing it when it fires (like to see things move plus saving the motor bearings).

It has worked out well.

The magneto supplies enough voltage to start easy using the engine crank and idles well at slow speed. For more information, write to me.