Bolens BL100, Had the same problem. Changed fuel, plug, carb (from an older model that was working), Coil assy. and primer bulb from same Working unit. Not a pop to be had but much cussing and about six hours work. Put a screw driver into the plug hole and slowly turned the shaft to determine top dead center and checked the flywheel magnet location-they were about 180deg. from the coil. Not good. Pulled the fly wheel off; not easy when the shaft just turns inside the fly wheel and the nut won't come loose. I took the muffler off and put a piece of fairly hard wood into the exhaust port above the piston to stop the shaft from turning and got the nut off. The molded in "key" on the fly wheel that is suposed engage the slot in the shaft was flattened and not engaging the slot. It did not look like it was sheared off; it was flattened and spread out to both sides. I think it happened during assembly. When the flywheel was put on, the key did not hit the slot but the operater drove the shaft nut home with an air wrench.
I very carefully Filed a 1/8th in. wide slot centerd on the key location about 1/16th in. deep; Filed a 1/8th thick key and put it togethr the old fashioned way. Not too hard to do if your half nuts.
Three pushes to the primer; second pull on choke; it fired and ran;Scared the #*&+ out of me after nothing happening for three days off and on.
Good luck
Philip johnson
April 2007