Chainsaw Repair

Here's with the muffler. He's using a HDA carb

There's a little neodymium magnet on the crankshaft hub and a Hall Effect sensor that sends a signal to a little CD ignition device.  I runs on a 4.8V Nicad or Nickel Metal Hydride Battery.

You can get the complete ignition unit for less than $75 made in China.

You time them at 28 degrees full advance with a degree wheel. The timing is not too sensitive. It is better if it is at least 25 degrees and improves a little better all the way up to 32 degrees but beyond that can be trouble and you start hearing the eggs frying.

When you start to turn the prop and pass the sensor with the magnet, the timing will retard to down around 4 degrees.

The advance is pretty much a straight line up to around 4000 - 4500 where it is back to full advance. Actually the advance (Retard) is there for ease of starting but it makes for a much better idle too.

They have a PIC 16 computer chip in them.