The suggestion of buying a new machine has to actioned only once I have determined that the problem is beyond me. Current Honda prices are above £300. I have use other makes, the only ones that come close are Stihl. They are 2 strokes, you can see them in the hands of most council maintenance teams. They are slightly cheaper but 4-strokes are easier to start if left unused for a period, like through the winter. When i had a bigger garden I tried several makes over the years, but Honda won out on starting every time.
Thanks John for the reminder on the Vibration white finger Regs. The vibration at present is just about below the threshold for induced problems, at least when I last used it.
WGW I believe the clutch mechanism has been known to cause problems on these and might be the first point of failure.
I agree with looking at the source of the vibration first. I have a feeling that it might be the head or the shaft, as there is no noticeable vibration when ticking-over on a concrete slab.
Perhaps some-one else has done a strip down of this machine. Hopefully You Tube and Google will be my friends.
Jerry