Small Engines (Lawn Mowers, etc.): B&S Timing....., starter rope, old engines

Question
I bought an old tiller that had been last started about a year ago. The engine is a B&S 130902... an old antique..lol. Anyway, I got this thing apart to clean the carb and all, pulled the flywheel and discovered that the key had been sheared. I replaced the points and condenser, setting the gap at 0.20. Replaced the flywheel and the key. Put the engine back together, spark plug is getting a good clean spark, fuel is being delivered by the carb. But when I re-installed the plug and pulled the starter rope, the engine fired and I got a "Kick Back", pulling the cord out of my hand. I know that this is telling me that I do not have the engine in proper timing and that the points are opening before "TDC".

My question is, are there any timing marks on these old engines ? How do I set the timing between the points and the flywheel ?

Hope you can help, looking forward to a garden soon....

Answer
The timing between the crankshaft and camshaft is achieved by lining up the timing marks on the two gears as it's assembled.  The points run directly on the crankshaft.  The timing between the crankshaft and coil is determined by the flywheel key.  The only timing that can be off is with the relationship of the valve events and the crankshaft (because the ignition is directly in time with the crankshaft).  It could be possible the flywheel key has sheared again.  There are several reasons it can shear immediately.  If you have the incorrect compression washer setup, the flywheel may still be loose and this will shear the key.  If the keyway in either the flywheel or the crankshaft is worn badly, a sheared key can result.  Another problem may be that if someone has previously monkeyed with this engine, it's possible they have incorrectly installed a lawnmower flywheel.  Lawnmowers use the weight of the blade for balance and to maintain crankshaft momentum and they are usually aluminum.  When there is no blade present, a heavier flywheel (usually cast iron) is used to provide this counterweight.  This is just a remote possibility.  You might also want to check the setting of your points again.  Spark is supposed to occur BTDC but an incorrect point gap setting can cause spark too far BTDC.  Also make sure that you have installed the correct flywheel key.  Some engines have keys with offsets and this affects timing.  Hope this helps.