shane55

I opened it and found a small cylindrical piece of metal about 1.5mm diameter and 2mm long embedded in the top of the cylinder head. The piston ring was not sitting in the slot properly at one end. I think the piece of metal might be part of the pin from  the piston ring slot. The piston ring is a tight fit in some of the slot while loose in the rest. I  presume the engine overheated and the piston ring slot deformed slightly. I have put the engine back together and it seems to turn over ok now, although a bit tight