Just checking my small generator before winter and has a rough idle.
Was gonna run some carb cleaner through it but all I have is fuel injector cleaner (Techron).
Will that work?

Techron may work, but it's for carbon deposits. Carb cleaner would work on varnish and small jet ports way more better. Often overlooked is valve adjustment, good to check it once in a while.

I take it this engine sits unused for long periods of time. Carburetors get "varnish"-like deposits from stale gas, not carbon deposits. If you put anything in the fuel tank, it should be something made for that. Before doing anything, run it for a while longer and see if it straightens out. Fresh gas running through it often cleans it up. The spark plug(s) may also be fouled.

Use non-ethanol gas if you can find it in your generator.

Fresh regular un-leaded non-ethanol gasoline for continued use especially if allowed to sit and not run....possibly Additives/stabilizers such as seafoam/stabil/etc..... Check the spark plugs for fouling................................. drill sgt.

The polyether amine in Techron can’t hurt. But, you want to ensure you dose it correctly.

Rough idle can be a tiny circuit in the carb body.

Find a small airport and get some 100ll avgas.
Works great in small engines and has excellent storage additives.
Usually costs about the same as ethanol free fuel.

Sea Foam in the fuel.