Hi,
I just bought an OS70 Surpass, which had obviously done a lot of running. I removed the head and cleaned out the inlet and exhaust passages, ground in both valves, re-set the tappets and started the engine. The compression is fine.
I runs fine, but when ticking over, it suddenly stops. This can happen even on a fast tickover. It makes a very slight pop sound, then slows down and stops, in about 2 or 3 seconds.
Any ideas as to the cause/remedy please?
Also what's the best way to adjust the slow-running needle on a 4-stroke. What are the symptoms of too lean/too rich?
Thank you.
Jack