You mean a socket wrench? (thats what we call them in Aus/NZ). Which side, the starboard side doesnt have a handle, just the lever, it also has an open bolt, where the port side where the lever is, is flush to the end of the pin/bolt that goes through the engine bracket.
I think you mean the port side where the actual lever is (it has a little rubber handle), this side, the bolt is flush with the end of the lever, not sure how it is held on actually.
When you say impacting, what does this mean in plain english (sorry i know things are lost in english depending on region, funnily enough English is a Western Germanic Dialect)
try a small impact screwdriver with the proper socket size. Being US mad Evinrude it is probaly english measures not metric... ...just try a few sockets with an extension
DEWALT DCF887B 20V MAX XR Li-Ion Brushless 0.25-Inch 3-Speed Impact Driver: Amazon.ca: Tools & Home Improvement
I never figured out port or starboard... I just go right or left looking forward
a few times....
Patience brings joy ....