12hp briggs on stratton on older Lawn Boy

[Dean_L]

Recently while mowing I noticed the motor starting to drag, I disengaged the blades pulled around the property to park it and when I did there was a loud pop, and the motor died. I tried to start it but it just turned over sounding a bit odd. Thinking the keyway at the flywheel sheared. I removed and inspected and found it was intact and fine. Then I pulled the spark plug and found the tip was smashed up. I turned it over looking in the spark plug hole and could see the piston moving, and appeared to be fine. I replaced the plug with a back up I had and when turned over, found it was smashed up too.

Any thoughts on what could be busted loose inside. Is this worth repairing. I purchased the mower used for 300 a few years back and have put about 150 into over time with a new carb and new tires.

Thanks

 

[Rivets]

Sounds like you have a major internal problem. Simplest way to find out is to remove the head and take a look at the piston and the valves.

 

[Dean_L]

That is what Im thinking, Im going to tear into it either tomorrow or Saturday. Ill update my findings