Had the opportunity to watch Steve put his injector cleaner tool to work and the results were fantastic. Having consistent fuel flow in each of the cylinders is essential to a smooth running and efficient engine. Marine engines work very hard and injectors get plugged and mechanics can spend a lot of time searching for the answer by changing plugs, adjusting timing, etc. when the real answer is plugged injectors and inconsistent fuel flow between clylinders. Give them a try, you won't be disappointed. And by the way, the equipment will also tell you very quickly whether there is a problem and if not, no servicing is necessary.