QuestionI have a Sears 6.75hp mower that is 3 years old. It won't start and I have changed the plug and the oil. When I pull the start cord it kicks back and pulls the cord out of my hand quite violently. I originally thought that gas was in the oil and this was what was causing the pull back, but it is still doing it after the oil change?
Any suggestions would be great
I thank you in advance!
AnswerHi Chris,
If it quit right after striking an object, I could almost guarantee that the flywheel key is sheared. A loose blade would have caused this also. The timing would then be off. The flywheel is located under the recoil/cooling shroud. Its' bore is tapered and mates with the tapered crankshaft. The keyway in the flywheel and shaft
keeps it from spinning on the shaft. A nut secures it. Use an impact wrench on the nut or a strap on the flywheel. Don't put force on the cooling fins or they will break. The recommended way to remove a flywheel is to use a puller. An alternative, is to tap on the crankshaft top, with a brass hammer or use a punch tip on an air
hammer. The flywheel will need to be held up and supported or upward pressure applied with 2 large prybars. (A 2 person job.) Care is needed so the flywheel doesn't crack or bend. Also be careful to not mushroom over
the crankshaft top. Replace the key. Install the flywheel after cleaning the tapers and re-tighten the nut to 65 ft/lbs.
There is also the possibility of a bent or twisted crankshaft depending on the severity of the impact but usually the key just shears.
Let me know how you make out.
Michael
