RE: where to buy an ehaust elbow for an old Kohler?
Daddyo,* You may want to figure out which engine is powering your genset.
The model number indicates to me it is probably a Perkins.* Often you can purchase parts for the engine that will adapt to your genny.
My Kohler 4kw is driven by a Yanmar 2gm and lots of the engine parts are sold by Yanmar that will fit my unit.