No lever on or near the left handlebar.
Here's the carburetor:
http://imgur.com/a/aFPAn
Left handlebar:
http://i.imgur.com/AbWPyCl.jpg
Right handlebar, for kicks:
http://i.imgur.com/GS4rfn5.jpg
Dashboard with the plunger thing below/between the two left dials:
http://i.imgur.com/janASre.jpg