For anyone who missed it, here is another copy of my TFC ignition timing degree wheel.
And now the whole story:
A while ago I bought a cheap 26cc motor which I wanted to convert to reverse rotation and use in a pusher configuration. A friend relocated the hub magnet and set the timing for reverse rotation but the engine was running very poorly after the conversion so I found myself needing to check the ignition timing to check if that was the cause of the problem.
So I drew up the attached degree wheel, ran it through a laminator a few times and cut it to size. Then I measured the ignition timing based on the attached video which I'm pretty sure I found in one of Al's posts. I tried the piston stop and the rocking method to find TDC and found both to be quite accurate.
It turned out that the magnet had been positioned correctly but the timing had been set (based on previous experience) by turning the engine in the normal direction. So when I checked the timing by rotating the engine in reverse rotation I realised that the timing was out by at least 20 degrees (equal to the width of the magnet) and this was the cause of the poor engine performance. I repositioned the sensor and the engine now runs as expected.
Cheap Chinese engines have a reputation of poor quality control so if your engine is not turning the RPM that you expected then it's easy to make yourself a degree wheel and check that your timing is set correctly.
New Downunder at its best
Linear Mode
