Thank you again vccomm for your quick reply and, you may have just confirmed my suspicions, as there is no resistance when rotating the blade at all with regards to compression. As such, tomorrow morning, I'll pull the head off and see if there is any issue with carbon build up on the valves caused by the sheer pin issue putting timing out. If there is no excessive build-up around the valve heads, then it has to be wear of the compression rings from age. Smoke wise, when running, the oil rings must be pretty good as there is little to no smoke from oil burn. Excessive oil and associated grime, at both ends of the crankshaft, would indicate the seals will also need replacing with a new set of rings.
As this belongs to a customer, can I get away with just a set of rings without knowing the full history of the mowers use? Maybe a changeover motor would be best option then rebuild this one as a future replacement for me or someone else?
Your assistance has helped confirm my suspicions.
Much appreciated.
Regards
Daryl.
