Simplified Webster Ignition

[IronHorse]

I was taking apart a couple of weed-eater motors the other day, looking for possible ignition parts for the Webster Gas Engine that I plan on building. One of these "Cheap" engines had an ignition system that did not have any points controlling the spark. I guess it just uses the relationship between the coil and magnets and the crankshaft to generate the spark at the right time. This gave me an idea, I could mount some magnets on the Webster flywheel in the same position as the weed-eater flywheel, And make it so the flywheel can be rotated and "locked at any position in it's 360 degree travel. I figure than it would be up to trial and error to find the best setting for the spark timing.

If this arrangement would work, it would make the ignition system very simple. No need for points, condenser or a battery.

What do you guy's think?

IronHorse

 

[Blogwitch]

What you are describing is a basic magneto, it generates it's own power to fire the plug.

This is my Minimag that I made driving a friends Webster.

[ame]http://www.youtube.com/watch?v=XiJphgWRZLg[/ame]


John

 

[IronHorse]

Nice running Webster, Bogs.

I think this ignition system would make a really "Clean" looking engine. I was thinking of mounting the coil in the base with a cutout below the flywheel to poke the coil through. That way it would be barely visible. Originally I was going to use the flywheel from the weed-eater, but I think it is too light and it is really ugly. I think I will just turn one up and fit some magnets on the perimeter.


IronHorse

 

[Blogwitch]

I am not sure about it, but I don't think it is just a matter of the coil and magnets. There should be some method of timing in the equation somewhere.

On my magneto it has a mechanical set of points, maybe on your old weedeater there could be some sort of small electronic bits with it.

John

 

[lee9966]

There is also a "little black box" that iirc senses the magneto voltage and then fires the spark. Also called an electronic ignition.

See this for a reference
http://science.howstuffworks.com/question375.htm

Lee