I have used it for several years in my motor. The thing I like about Seafom is it will do multiple things. It is a fuel stabilizer so it helps prolong the amount of time before fuel will break down/phase separate. It also will clean the fuel system/injectors/carburetors. The best part is it also cleans carbon. Most fuel treatments do what Seafoam will do but the lack carbon cleaners.

To do a through cleaning you can mix an entire can in a portable six gallon gas tank. Then hook it to your existing fuel line and let it run on a water hose for 15-20 minutes at idle. Shut the motor off and let it sit overnight and then take it to the lake the next day. Fire up the motor and let it idle for a few minutes then get on plane and vary the RPM's from low to wide open until you run the portable can empty. Somebody explained a method similar above and I suppose it works too.

Once you have your motor clean of carbon you can run what is called a maintenance dose...I can't remember the size of the can. I am thinking 12 oz or possibly 16 oz. I remember the can said you can mix the entire can in 28 gallons of fuel. I typically buy 10 gallons of fuel and pour in 1/2 of the can. My maintenance dose is a little higher. I use the entire can for 20 gallons of fuel...not all the time but most of the time.

Kind of off the topic but...one of the best ways to prevent carbon build up is to run a 100% synthetic oil. I prefer Amsoil HP Injector oil. It's about $35 dollars a gallon. A cheaper alternative is Pensoil Marine 100% synthetic. I have seen it for $20-25 a gallon at Wal-Mart. Bass Pro will sometimes run it on sale at a decent price.