Saw not firing

If this is a stihl saw....they are notorious for bad electronic ignition, as evidenced by blackened plug (weak coil).......Replace coil assy. and hold an air gap at the magnet on the Flywheel by placing a business card between the magnet and the coil assy. while tightening the bolts on the coil....This air gap is critical so be careful that the flywheel is not contacting the coil assy. attach the small wire to the coil for shut down function.........

is this question about a two cylinder saw ? if so its an oldie but I like em !! seems that two cylinder 2 strokes can develop points issues that fire the coil twice on one cylinder only (sometimes saw will run , with little power) , ck points time, this assumes of course that you've got a single coil with two wires exiting it , dual coil saw? id ck the coil that doesn't fire with a ohm meter

Make sure you are using a resistor plug. This is extremely important on this model. If this is not the issue, remove coil, use emory cloth to clean the mounting area for the coil. Trash or oxidation can prevent a good ground on the coil. Lastly make sure the air gap (distance from flywheel to coil is correct) itshould be .012"

check to see if your magneto is rusty if so clean with fine grit paper if still does'nt fire may be time to replace the magneto

i would suspect coil to flywheel distance too great

Plug may have weak spark, as odd as it sounds it does happen, try fresh plug.

Try a new spark plug.If still does not fire you have a bad ignition coil.

check the fire to the coil pack if it's present then check the pulse to the crank sensor

check wires an plugs also

Four things I can think of:
1) There is a short in your spark plug wire. When you bend it to connect the plug in the machine it allows the exposed cable to contact the engine block. Examine the wire all the way to the coil.

2) Flywheel key is sheared ( you obviously know how to take off the flywheel since you checked the seals).

3) Flywheel air gap is not set correctly. Loosen the coil. Put the cover of a notebook or the cardboard piece of a cigarette pack between the magnetic portion of the flywheel and the coil. Tighten the coil down. This will get you the proper gap.

4) Your cylinder/piston or rings are scrubbed out. Even though it passed a compression test, on rare occasions it will loose compression only when it fires. So do the following:

Remove your exhaust manifold. Look into the cylinder with a flash light. You are looking for scratches. Anything larger then a light fingernail is definite proof you need a new cylinder/piston assy.

If it passes that test do the following:

Pour mixed fuel straight into your cylinder until 1/4 full. Slowly pull your saw over while looking into the cylinder. If you see bubbles after the ring/rings go by then you need a new cylinder/piston assy. On rare occasions if no scratches are present on the cylinder wall or piston, you may be able to change just the rings.

First if you can get a inline spark tester so you can see if your getting spark with the plug installed.