It wouldn't take much to improve this design and make it actually work. I think is this was milled correctly to clear the pump arms and keep the cable low this thing would work perfect.

Yes I can get the blades to actually go past 90° if I move the linkage on the carb by hand.

I pulled the spacer out of the back. Now the cable sits a bit lower and gave me a little more throttle. I just hope the bracket doesn't crack from the flex and vibration.