Hi,
It’s been a while since I sorted it. I ended up acquiring it, so it came back to my workshop and I completely stripped it down.
Turns out the piston rings have had it, and there was some scoring of the cylinder.
I honed the cylinder and fitted new oversized piston rings and that seemed to solve the problem and it worked quite happily ever since.
To be honest, I haven’t ran it for over a year so I think I need to drag it out and run it for a couple of hours.
Thank you
Luke