How to use Seafoam Motor Treatment for outboard motors

Seafoam Motor Treatment is a popular brand of engine cleaner used in two- and four-stroke diesel engines. Although it is used in all types of engines today, it was originally developed specifically for outboard boat engines. Over time, fuel and oil leave residue in the crankcase, around the pistons, and on the carburetor nozzles. The purpose of Seafoam is to dissolve this residue. After treatment, you will notice an improvement in engine performance.

Two-cycle motors

Add Seafoam only to a nearly empty fuel tank. This is to make sure you have the correct Seafoam / fuel.

Prepare your normal oil and fuel mixture. Add 2 ounces (56 g) of Seafoam for every gallon (3.78 l) of fuel.

Pour the fuel mixture into the engine’s gas tank.

Start the engine and use it as usual. The Seafoam will dissolve the deposits as the fuel mixture passes through the engine. A good indicator that the Seafoam has done its job is the reduction in engine smoke.

Four stroke engines

Drain the engine oil and change the oil filter.

Change the engine oil, and add 1.5 oz (42 g) of Seafoam for every quart (0.94 l) of oil you added. The Seafoam mixes with the oil and dissolves the sludge from the crankcase and lifters.

Add one ounce (28 g) of Seafoam per gallon (3.78 L) of fuel in the fuel tank. Best done when the tank is nearly empty to make sure you have the proper Seafoam / fuel. Seafoam will dissolve debris in fuel lines and carburetor jets.

Run the engine normally, but check the oil frequently. The Seafoam will cause the oil to become more dirty than normal. When you see that the oil is dirty, change it next to the filter,


You can also add Seafoam to gasoline to stabilize it for up to two years


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