SuperChris

You may have put the float level too low, And are starving the thing. It sounds like you might be talking about clutch slippage also if when you hammer on it, the motor revs up, then slowly starts to bog.

Is this a common failure? Will it make a big difference in how my Banshee cools to get and aftermarket impeller?

If you'd like, I can send you my spare right carb to try out.

Did you look to see that the choke hose was connected?

I had a twist throttle on my Banshee when I got it. I have since switched to a thumb throttle and the cable only needed a minute and a half worth of modification. Dont waste your money on a new cable untill you try your old one. I'm almost sure it will work. The stock banshee I swapped my twister for also had a stock cable that needed no modification to use my twister throttle. If you cut the springs down on your carbs, it will help your thumb out tremendously. Just don't take to much off at a time.

I have been running on .100 bores for quite a while. Very reliable if you ask me.