So you are going to put this on an airboat. Just in case it hasn't been made clear earlier, you will need a way to retreve the boat from the water. You've learned that this is an ON/OFF type engine which means there is not way of controlling throttle. I, however, am not sure that you know that once the boat is launched you do NOT get to controll the OFF. It will shut down when the fuel supply is exhausted. That means in the middle of the lake somewhere. Just a little FYI for your planning purposes.