gy6 backfire under deceleration

[buggykid]

Hi my engine keeps backfiring and it's not stopping it's starting to get really annyoing. I want to know what is the problem and how can stop it.

First when I bought the thing used i worked great no backfire nothing was wrong with the engine, until the carb got contaminated from rusted metal particles in the gas tank the kart would not start at all. So I took off the carb and it was really dirty so i cleaned everything. The thing i regreted was when i took out the air/fuel screw and cleaned in there, and eversince i have cleaned the carb it has backfired. The backfire is not some little puffs either it's close to a gunshot it's pretty loud and i dont want to ruin my engine because of this.

So far the exhaust is not leaking and the intake boot is not sucking in air it's just a carb adjustment. I have read that the main cause is because it's to lean and i'm not sure where my air/fuel setting is supossed to be. where do yall have your setting at or where can i start?