I bought an old 160cc power torque mower cheaply....ther engine turned over nicely and there was heaps of compression. I took the head off to clear the carbon out (it was about the worst id ever seen!) and 4 little metal rods (about the size of a plastic carby jet needle) were amongst the debris inside. I wound the motor over with the zip starter but it seized up as another one got caught between the top of the piston and the inlet port. I reckon the motors rooted now. Anyone know what these little pieces of metal were? Also on this mower the barrel and the crankcase are all in one.....how on earth can you change a piston on one of these?