I see two Bowden cables. One for choke the other maybe hand throttle?
The Monojet throttle lever was designed to connect to a throttle cable or a link from a bell crank.
Your engine has a throttle rod so I guess it was modified to work somehow.
A spring goes where your black arrow is shown.
You may be missing a choke link.
Attachments
Monojet Linkage 01.jpg (88.87 KB, 61 downloads)
Monojet Linkage 02.jpg (27.06 KB, 61 downloads)

"Adding CFM to a truck will only help at engine speeds you don't want to use."
"I found there was nothing to gain beyond 400 CFM."