Not a fuel injector. It's a throttle body of some sort. Might try posting a pic or two showing the other side. I'm trying to decide if this is a side draft vacuum diaphragm type carburetor or not.
I have to admit; no idea. There are some oddities I cannot figure out but looks like more of a side draft, vacuum diaphragm carburetor to me than anything else. I've done a lot of work with carbs like that in the past but have not seen one like the one pictured. I rummaged through some of my old manuals and cannot find anything similar. Sorry I cannot be of more help.
Possibly start with a measurement of the throttle body opening at the flap, usually measured in Millimeters. This would be a good start at identifying the application- google is a good help with this.
