Not to be a smart A, but are you sure the key is not sheared. Are both key grooves perfectly lined up. If the key is not sheared, you are going to have to pull the side cover and check the timing marks on both the crankshaft and camshaft. If you need two hands to pull the engine over, either the valve timing or ignition timing is off. Easier to pull the flywheel and check the key, than pull the side cover.
It's on myTiller I hae owned it over 20 years It has always been had to start yanking the cord out of your hand. I have never had it apart till now. Still haven't found problem Its on a MTD tiller sold by ACE Hardware
Iron flywheel...….Pulled other side open timing marks line up. Pulled head valves open and close but when turning engine over on exhaust stroke it turns easy . On intake stroke it seems to get harder to turn. What are the chances of a bent valve stem? The seats look good and there are no marks on the valves. Have not pulled side cover under valves
I noticed there is play in rod to piston at TDC. With cover off crank side I turn crank and there seems to be a few degrees in crank turn before piston starts back down. My thought is intake valve is opening before engine fires causing it to refire. Am I making any sense? I have built lots of V8 engines and there is no lag at TDC. The piston is on its way down as soon as it hits top. Guessing piston.. rod bearing.. crank?
Well I couldn't find the problem. I took it to a repair guy that works on small engines. He checked it out and couldn't find anything wrong. SO he took the carb off again to rebuild it thinking he missed something. There is a brass tube that goes from the carb to the gas tank. While cleaning it again he noticed the cleaner coming out the side of the tube. The tube was split most of the way up so it was sucking air. He said that was why I had to run it with choke part way closed and that loaded it up with fuel. Causing it to kick back.. All I know is it starts like new now. Thanks for all the input.