2 stroke weed eater ignition timing

What is ignition timing supposed to be for a small 2 stroke like a weed eater or ice auger?

Usually the ignition timing on these is fixed by the magnets on the flywheel magneto on modern ones with electronic ignition the gap between the ignition sensor and the flywheel has a very very tiny effects on older models the points gap has a more significant effect

Andy.MacFadyen wrote: Usually the ignition timing on these is fixed by the magnets on the flywheel magneto on modern ones with electronic ignition the gap between the ignition sensor and the flywheel has a very very tiny effects on older models the points gap has a more significant effect

Thank you, and yes that's all true but I'm looking for the ignition timing spec. I am diagnosing a small engine and want to know if the flywheel has turned without having to take anything all apart.

From what I found, 8-12 degrees BTDC. I figured. Combustion is the same. Well, now we know.

How does one check the timing on a weedwacker? Are we doing some fancy scoping (is that a word?) here? Pictures & video, please. Inquiring minds want to know.

Pressure transducer in the cylinder and capacitive pickup on the secondary ignition wire.

I'm suspecting based off a symptom that the flywheel has spun and I want to confirm it without taking anything apart.

Really old methods are more suitable mark TDC on the flywheel and crankcase and use a timing lights, but as any I have worked on have flywheel keyed to crank it even easier just take the nut and washer off to do a quick visual inspection.

Faulty ignition module.

Timing starts at 8 degrees and gradually advances to 40 degrees. Key is in tact. Flywheel ok.

The engine tries to run backwards due to advanced ignition timing.

Ahh, I missed this one! This stuff is my bread and butter - way less stress than working on cars. Paul has made my stress level go WAY down over the past year with some new knowledge, however.

I usually just remove the nut if I suspect the flywheel has spun - you'll see the channel for the keyway offset from where it's supposed to be, if it spun. Quick and easy check. Works on mowers, and lawn tractors too. I love the stuff - so simple to make it work.

The old R5 & RD350 Yamaha motorcycles from the 70's were famous for running backwards ( I own a '74 RD that I fully restored in '09 ) - what a surprise when you let the clutch out when the light turned green!!