464 S. 5th Street Sebewaing, Michigan 48759-1559
Ignitors should have a set of contacts at least 3/16' in diameter, ' would be better yet. If you have only, say, ?' diameter, you don't get the large size arc that you need to really fire up an engine. The points should line up flat to flat.
There's an ad in GEM that has ignitor points for sale at a really fair price.
Gas engine companies made ignitors two ways: If the engine was made to run on a battery, the ignitor points would be normally open, and that ignitor would have an extra spring on it to hold the points open. The reason for this is, while the hit and miss engine is not firing, it is not taking any current out of the battery, and the battery lasts longer.
The other type of ignitor is the one used on an engine with a low tension magneto. The points will be normally closed, which does not matter, as the current is coming from the magneto.
If you are using a battery/coil set up to run an engine that was made to run with a magneto, you can usually hook a spring somewhere on the ignitor to hold the points open, and you will find that your battery will last longer.
Low tension coils that are used with ignitor engines vary in strength. I have some old round type gas engine coils that I have checked with a V.O.M. ohm meter and they check out at ohm resistance, and that is very good. I have checked some others and they have as high as 1 ohm of resistance. The 1 ohm doesn't make nearly as large an arc at the points as the ohm coil does when the ignitor opens.
Some fellows use an old car coil. There again, they will vary from a ohm to 1 ohm.
I have used 6-volt and 12-volt batteries. I find the 12-volt batteries will pit the points quicker than if you use a 6-volt battery.
I see some engine owners using a small square 6-volt battery. That small battery just doesn't have the amps and volts to really fire up an engine. I have a test box that I made with a DC voltmeter and DC amp meter. When I wire this up with a small flashlight 6-volt battery, when the engines fires the voltage will drop to 3 or 4 volts and, depending on what kind of coil I use, the amp draw from the battery will vary from 2 amps to 15 amps.
I expect to get a little flak from some of you gas engine people about the above story, and that's okay, I really enjoy getting your letters.