I would stick an electric fan on from the breakers mucker them things seem to overheat a lot.
The mini had more power in the starter than the engine, when you cut em you also cut the flow just the same as taking the cowling off because it sucked the air through and a bad idea.
If you go electric fit the fan on the grille side of the rad and the thermal switch at the top of the rad. The kenlow switches are not so good so look for another type.