Good day David here, just thought I would mention "the missing o ring" I have pointed out with the white pen where it is missing. The saw has low compression only 6 bar about 90 psi, the research that I have done is that there will be a pressure leak, causing the top end to overheat/lean out, I am not an expert on these. I have bought a new top end kit and before fit it I am going to do a vac/press test, with my Mightyvac 8500. I have been advised that instead of the o ring one can use heavy grease, and then sliding on the sleeve and washer, and the rest of the oil pump,clutch etc, but I am going to go the o ring route.