Re: reason behind turning the fuel petcock off?
With 2 strokes, the worst that happens is the engine floods and gas gets everywhere (bad enough in itself, don't get me wrong). But you let the spark plug dry out, clean the mess up, and eventually the engine will start again just fine once all the fuel is out of the engine, as long as there is fresh gas in the tank. On the subject of petcocks, the carb petcock by itself is not enough to stop fuel from leaking out of the tank. I've had fuel leaks with the tank petcock open and the carb petcock shut. Its best to either use the tank petcock or an inline fuel valve. If the one that comes with the kit works, use it. If not, you can go to just about any hardware store and get a threaded nipple and a ball valve. Screw the threaded nipple on or into the tank threads, attach a small section of fuel line, then install the ball valve and connect the other end of the fuel line to the carb. I have done this and its worked good for me. Now onto the subject of 4 strokes. If you dont properly shut off your fuel on a 4 stroke, straight gas can leak into the crankcase and thin out your oil, which is a little worse than dealing with flooding on a two stroke. I believe that gas leaking into the crankcase is responsible for the failure of more than one 4 stroke engine on this forum. As it happens, I've got a petcock on my tank and my carb, and I use them both. In fact, I crashed about a month ago and my carb petcock lever snapped off in the open position. I could have left it that way and just used the tank petcock, but I was concerned that even the tiny amount of fuel in the line could seep into the crankcase. So I found a replacement fuel shutoff lever as quickly as I could. I feel much more comfortable knowing that with both petcocks shut that there is almost zero chance of fuel seeping into my crankcase.