Originally Posted by 49clipper
On a different line, I just bought a Rotec TBI for my new project. Sounds like you liked your Ellison. Good to know, but what is to "tune" on a TBI. Sounds like there is nothing on it but an idle screw and the linkages. Just wondering.
As you well know, Throttle Body Injection goes way back to early engines and auto racing. The Wright Flyer engines actually have a rudimentary TBI on them.
Tuning the mixture is simply rotating the injector nozzle in the air slipstream as it flows through the venturi which varies the fuel mixture. Ellison uses a diaphragm in lieu of a float chamber to draw fuel into the venturi. A poor running TBI can usually be traced to one of these two items.
For your Rotec, the Sonex guys had a good thread on the topic, link below.