OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines 5hp Briggs

I just pulled the head off a 5 hp B&S that would rotate not quite 360 degrees, would stop at TDC when rotated in either direction. It had been running fine, no smoke or noises. The bore is now scored in a few places and what was preventing it from rotating completely was a couple of small lumps at the top of the bore that the piston was hitting. Any thoughts as to what would have caused this.

on muffler side ? or where abouts are these lumps or dents from maybe bolts too long .......... maybe

Hi Norm, post a couple of pictures if you could. They will go a long way in identifying your problem.

Hi Ted, I don't think I would bother repairing it, bore is shot, just curious as to why it did it I cleaned of the little deposits with a dremel and it turns over fine

Yep, the bore looks fairly gouged. As to what caused it, that my friend is a mystery, especially if there were no pieces of valve, seat or piston in there.

If it had been severely overheated, then left with the piston near TDC to cool, semi-melted bits of the piston top land could have welded onto the bore, as they are both aluminium by the look of things.

You'll have to pull the piston to see if this was the case. Anyway, that bore isn't a pretty sight!

Yup she is a bin job, the top of the piston looks fine from what I can see, don't think I will even waste the time pulling the piston, I have pulled the motor out so I will just fit a new one.