I got a couple of mowers off ebay with rotted decks just to get the engines. The wife decided to mow a concrete kerb and it won. She managed to bend the crankshaft.
I though I had straitghtened it but the vibration was so bad it gave me white finger...
I was amazed how cheap a briggs and stratton engine looks inside compared with a Honda.
I hit a buried scaffold pole in the summer with an Etesia mower. Blade - fine, deck - fine, engine - fine. Took it to the mechanics just on the safe side.
Took it out few days later, used it for maybe 10 minutes, and the bolts that held the engine to the deck all sheared
I've no idea what it hit Dave - I let the Mrs take care of making the place look pretty - I just do the demolition, construction and maintence. All she said is that it went bang and stopped!
Thing is, B&S + Hayter are meant to have a friction mounted blade so if it hits owt then the engine is 'safe'
One of the reasons that it _may_ have broke is that the Piston and con rod have been fitted together 180 degrees out of phase and then mounted in the engine block incorrectly - according the the B&S repair manual that I 'found' online, they have to be fitted with the 'notched side of the piston and the 'mag' side of the con rod on the side nearest the magneto. Well, the mag side of the con rod was furthest away from the magneto.
It's a secondhand engine/mower so I suspect someone else had been in it before me ...