Sort of motor not allowed to go on (8)
I believe the answer is:
outboard
'sort of motor' is the definition.
(I've seen this before)
'not allowed to go on' is the wordplay.
'not allowed' becomes 'out' (I've seen this before).
'to go' becomes 'board' (I can't justify this - if you can you should give a lot more credence to this answer).
'on' is a charade indicator (letters next to each other).
'out'+'board'='OUTBOARD'
Can you help me to learn more?
(Other definitions for outboard that I've seen before include "Small boat's motor" , "Engine external to the boat" , "Type of boat engine" , "Sort of motor" , "Engine mounted at the stern of a small boat" .)