Hi Festing

BB is unwell at the moment.

Whether the clutch engages or disengages is dependent upon
the condition of the components. The clutch lever has an eccentric
slot that determines the throw (travel) of the clutch cone.

If the cutter keeps cutting 'at full speed' when disengaged then
the issue will be:

- no or little cone travel
- worn thrust bearing
- worn thrust pad
- incorrect adjustment
- poor set

Could you please confirm that the reel is making contact with the bedknife.
They require contact to create slight drag that prevents reel free-spinning.

I feel it may be time to unbolt the motor and have a good look.
Hope this helps in BB's absence.

--------------------------
Jack