If you see white billowing smoke when you start your outboard boat motor it might be time to decarb it. "Decarb" is short for the term "decarbonization," which means to decrease the amount of carbon in a metal. Over time, carbon buildup on the exhaust chamber walls of your outboard motor can cause problems like smoke, odors and rough idle or engine performance. There are simple methods of dealing with this probem that will cost you little money or time.
Remove the primary gas tank from your boat.
Mix a 16-ounce can of Seafoam Motor Treatment with approximately 3/4 gallons of fuel in a spare gas can.
Connect the secondary tank to your boat's fuel intake port.
Start the engine and let it warm up for a few minutes.
Squeeze the primer ball on the secondary gas tank and allow the motor to pull the Seafoam-fuel mix in. Allow the engine to run for 20 minutes.
Stop the engine and let it sit for 20 minutes.
Restart the engine. If there is no more smoke you have removed the carbon buildup in your engine. If it still smokes a little repeat the process until you no longer see white smoke.
