Hi guys.. I have a 2001 8hp yamaha engine that has only been firing on one cylinder. I pulled the plugs (Which were both recently replaced); one looks new, and the other looks used.. I grounded the plugs and pulled the starter cord; only one of the plugs fires. Pulling the plugs and switching them shows that both plugs work. Is this a problem with the ignition coil? The spark plug wire/assembly? both?<br /><br />Also, recently, the engine ceased to start up at all, even under just one cylinder.. I fear that the carberator has gotten junked up, but hopefully getting this cylinder issue will make it all work again 
TIA!
TIA!