On first test ride, the engine ran good. Made a couple of trips up and down the block. got full acceleration. The engine chain installation was shaky, so it sat unused for only 1 week while redoing the engine chain (ended up removing tensioner). On test ride now, the engine starts every time, but it will not accelerate at all from a low idle. After about 5-6 seconds, it dies. I can see the line going into the carb is full of fuel. Also, throttle feels the same, and as I go from idle to max, the tone of the engine changes a little, but not speed. Experimented with idle screw adjustment and throttle adjustments but no luck. How can the gas go bad in a week? Still, should I dissasemble and clean out carb?