MOPED ARMY

Owen, the way a two stroke works, while the piston is traveling up, it creates a vacuum in the case and thereby causes it to draw air/fuel mix into the case thru the carburetor and intake. On the Piston's downstroke, it forces that air/fuel charge into the cylinder, where it is compressed and burned in the next upstroke. If your crank seal is bad, your engine will draw air past the seal into the case as well as drawing air/fuel mix thru your carburetor. This will make the air/fuel mix way too lean, causing a poor start/run condition, will cause your engine to overheat and may actually seize your engine.