Be sure to set the point gap before you time the ignition - the size of the gap changes the timing. Setting the timing is not a very precise process. I suggest you set it for 5 degrees before top dead center. If you advance it too much, it will kick back on the pull-rope when you are starting it; aside from that issue, more advance will increase the maximum power, but kick-back is actually dangerous, and you don't want anyone getting hurt. 5 degrees is a reasonable, fairly conservative value that is not likely to kick back so long as the rope is pulled at normal speed or faster.
To locate a firing point mark on your flywheel, measure the outside diameter of the flywheel and multiply by 3.14. Then divide the result by 72, which gives you the required distance in inches or millimetres before TDC. Make a stationary mark on the engine in a visible place. Temporarily install the flywheel and find the point on the outside of the flywheel where the points start to open. Make a permanent mark on the flywheel there: this will be your timing indicator. Measure anticlockwise the 5 degree distance calculated above, and make a narrower permanent mark on the flywheel at that point: that will be your TDC mark. Next you set the flywheel on the crankshaft in the correct position. Put the crankshaft carefully on TDC, then slide the flywheel onto the crankshaft taper with the TDC mark aligned with the stationary mark on the engine. Rock it back and forth, to check the piston is actually on TDC when the TDC mark is aligned. Tighten the flywheel retaining nut. From then on you can use a timing light if you want, to check the ignition timing. To make small adjustments in timing, you can adjust the breaker gap rather than taking the flywheel off again, but if you do this, check that the breaker gap is still close to the correct value or you will weaken the spark. Of course if you have timing adjustment slots in the breaker point mounting plate, you can slide the points on those to make fine timing adjustments, while still keeping the correct breaker gap.
