Thanks Chris and Theo,
Well��
I changed the carby shell thinking that might be the problem however I didn�t have another working power torque around to try and known one but I did have a wrecked one. I swapped the carby shells and the problem was still the same. The engine would idle ok, albeit a little rich and then when you move it to full speed it only had a very light change. The engine was still running super rich.
Option Two (tried the one ring jet)
Mower started on the first pull again and it fired right up with good speed however the speed setting was everywhere. It was revving ok at the start but then it started to rev up and down without touching the throttle controller.
The mower had a plain face jet when it arrived and the like I said earlier the guy was adamant it just stopped. The previous owner did say it always went without a problem.
I think I am down to the last option (that being to tear out the crank bearings and replace them. They were slightly noisy when the engine actually fired up.
Any suggestions would be appreciated.
[Linked Image]
[Linked Image]