Hi
C15 engine is stalling when I pull the clutch in.
What causes this to happen.
Badly adjusted clutch......if you put it in gear with the motor off, can you push it with the clutch pulled in? If not, search "adjusting clutch"
I would also pull the plug and check that it will push in gear...if it stalls as you pull the clutch in, whist still in neutral) there is something running tight or seized in the box or the clutch.