you are correct if air is entering the engine unmetered it will afect the tune but the fuel you are seing is after combustion if you had a pipe on your engine it would be comming out the stinger tip it is like when you have an engine that doesent start righit away and you pour raw fuel out the pipe the K&B engines like to run rich and ther is usually unburnt fuel when idleling and low speeds and if you could see it it goes away with high speed passes as the engine leans out with a load on it