I had the same problem with the throttle shaft to. the new lever arm on the new carb dosent work with any rc type set up. i tried to change out throttle shafts and they were just different enough that all it did was beat up the butterfly valve.

I plan on trying to make a new throttle shaft with a much longer rod to be able to install a throttle arm in a much better location that will be more usable when i get back with some machining capabilities.

the carb i used already had a nice choke so all the choke modification wasent nessacary and sure makes for a nice install

I should be back in a few days and I can get back to doing some testing lol