Chainsaw Repair

The only saws I seen 4 stroking and hitting  the coil limiter to date was the poulan 505 475 I have.  Their dang rev limit coils was around 10something. If I remember right. Crazy low.

That is really low.  Like a demo saw coil. 

Good thought to measure before replacing OEM coil! I have run into aftermarket coils that do not have the mounting bolt holes in exactly the same places as the factory coils and sometimes even the core elements are off by a little in relation to the mounting pattern, so you may end up with a ignition timing change just by bolting the thing into the saw! Don't see this much on the later Chinese made coils but did see it a lot in the earlier ones.

You might also want to consider snooping around for a used OEM coil, then you know that the thing is built the was HVA intended it to be built.

There's a thread around here somewhere - a well respected guy was using a timing light. It gave a arbitrary reading, not what I would consider to be a actual reading. It worked out OK for him, for he timed the new type coil to the same number.

My experience with hopping up weed whackers, they are most often in the 22-25 degrees advanced range with the stock flywheel and coil. I put hall effect triggered electronic ignitions with computer controlled timing advance. The total advance I used was 28 degrees with an error towards a little more advance. A 25 -30 cc weed whacker did OK with a fixed advance at 28 degrees but getting into chainsaws above 40cc you need retarded timing to get the engine going of somewhere around 16 degrees without kickback. I always timed them statically with a degree wheel. They timing curve was not too scientific as they were full advance by 5500 rpm.

The moment the magnet leaves the coil armature