Small Engines (Lawn Mowers, etc.): B&S 4hp, camshaft timing, point gap

Question
The flywheel key is not sheared ( there was nothing wrong with the old one) but I put in a new key anyway. The is oil level is normal. are you saying there is another key where the hub & blade attach? if it is the timing how do I reset it? Thanks, Don

Answer
There will be some type of key in the blade hub, that if sheared will cause the blade and hub to send forces back through the crankshaft that are similar to hitting a stationary object and will cause the flywheel key to shear.  The timing is set by the alignment of the crankshaft and camshaft timing marks and will not have changed unless the engine has been apart.  The only other things I can think of that would cause the engine to "kick-back" would be the point gap (if equipped with points, gap should be 0.018 - 0.020") or the armature-to-flywheel gap (should be 0.010") causing the timing to be out enough to make the engine kick back.  I can't think of anything else that could cause this besides what I've already mentioned.  Unless the keyways in the flywheel and/or crankshaft are damaged.  Hope this helps.