carb issue?

[AlienYouth]

so, my gas gauge is broken, but i didnt know that... i ran out of gas, but didnt figure that out for a while... so while i was troubleshooting, i put the filter on backwards and flushed all the crap it caught over the years into the carb... something was keeping the needle valve open so it was shooting gas out, so i rebuilt it, no more gas shooting out, but know to the main point... when i give it a good pedal of gas is sputters and backfires, and i have to give it less gas as the rpm's go up to keep it from doing so... any ideas? thanks