Your newest coil is oem? Do you know someone that has the exact same working model, that you can pull their coil, try it on yours, and if it doesn’t work, put that coil back in theirs and make sure it still works ? (To verify something isn’t frying the coil repeatedly)? I would also do an MPEM swap test.
Here is a response from AI:
A few things to check or re-check:
1. Battery ground location:
Relocating the battery ground from the starter to the cylinder jug can work, but it introduces variables. The starter bolt is ideal because it’s a direct mechanical and electrical path into the engine’s core grounding system. Try grounding to the starter just to fully eliminate grounding as a culprit — a poor or inconsistent ground can absolutely kill spark even if you’re getting a pulse on the white wire.
2. CDI or MPEM weakness (even if it beeps):
Getting the two beeps means the DESS post is likely working, and the MPEM is at least alive, but that doesn’t mean the CDI/MPEM unit is functioning 100% internally. It might still fail to trigger spark. If possible, try swapping in a known-good CDI or MPEM from a friend’s ski or even a cheap eBay one for testing.
3. Spark test method:
You mentioned testing spark with the wire near the battery terminal — but are you grounding the plug wire solidly when testing? Try inserting a known good spark plug into the boot, grounding it solidly to the engine block (bare metal), and cranking. Sometimes the arc won’t jump unless there’s a path with correct resistance like through a plug. Bare wire to terminal isn’t always enough to trigger a visible spark.
4. Trigger coil gap:
You said you verified the trigger bracket is intact, but also double-check that the air gap is correct — too much space and you won’t get a good timing pulse. Should be ~0.020” (0.5mm) between the pickup and flywheel lobe.
5. Timing/flywheel key:
If the flywheel has sheared the woodruff key (especially if it was removed during the oil drain), timing could be off even if the flywheel feels tight. That would cause no spark or spark at the wrong time, which would be invisible during test light probing.
6. Coil polarity / connections:
Make sure your new ignition coil is wired correctly. Some aftermarket ones swap terminals or have reverse polarity from OEM. Make sure the white wire is to the correct post and that the black is grounded properly.
