Thanks for the question, Christine!

Yes, you can still add Sea Foam. It will still stabilize and protect the fuel in the fuel tank. Add a minimum of 1 oz per gallon of fuel in the tank. Adding a whole can works too if you want to go the simple route. Adding more than 1 oz per gallon is fine and will do a good job cleaning up any fuel residues when you run it in the spring.

Thanks for the question, Michael. Yes, it’s okay to mix Sea Foam Motor Treatment (traditional) and Marine PRO. However, Marine PRO will do everything that Motor Treatment does, so you could just use that.

Thanks for the question, Jim! Yes, you can use Marine PRO in a car. It won’t hurt anything and will still do a good job cleaning up the entire fuel system, just like Sea Foam Motor Treatment.

One tip: I like to wait until the tank is low (1/4 -1/8 tank), add the whole 20 oz can, and then drive for at least 10-20 miles before refueling. It’s safe to add a high concentration like that and it works very well for cleaning fuel residues and deposits.

Thanks for the question!

Lots of people use Sea Foam as preventative maintenance to keep their engine in the best shape possible. Sea Foam cleans and prevents fuel residues and deposits from forming in critical engine areas, and a cleaner engine will run better, last longer, and avoid problems caused by a dirty fuel system.

Sea Foam is safe and effective in any type of engine and works great to keep things clean and running well.

In boat engines, add 1 oz of Marine PRO per gallon of fuel to every tank of fuel. Once a season, run down the fuel tank until you have 2-3 gallons, add a full 20 oz can of Marine PRO, and run it until almost empty.

In cars and trucks, use Sea Foam in fuel about every 3-5,000 miles. Add a full can of Sea Foam to a low tank of fuel (2-4 gallons), and drive until almost empty before refueling. You can also use Sea Foam in oil to clean and prevent oil residues. Add 1 oz of Sea Foam per quart of oil 100-300 miles before an oil change.

Thanks for the question, Kevin. Yes, you can add Sea Foam with fuel that already has oil mixed.

Here’s what I’d do: Wait until you have a low tank of fuel (1-2 gallons). Then, add a full can of Marine PRO to the fuel. Run your boat at least 20 minutes if you can (just don’t run out of gas!), and don’t be afraid to run it hard. After that, refill your fuel tank as normal.

Here’s a (rather lengthy) explanation of why a high concentration works best. For upper engine cleaning (fuel injectors/carburetor circuits & chamber deposits that can affect running performance), it works much better to add the full can to a low amount of fuel for two reasons, 1) the cleaning concentration is considerably greater and, 2) the cleaning effect will start much faster with greater effectiveness. If you were to add Marine PRO to a high volume of tank fuel, it might take several hours of engine running for a lower concentration of the treatment to work its way through the fuel lines and through the engine. Understanding the concentration approach will go a long way in terms of understanding how Sea Foam’s engine products work for overcoming fuel residue restrictions or a rough-running engine. Pay attention to starting, smooth idle, throttle response, hole shot, acceleration, and top speed. The #1 cause of each of these issues is heavier suspended fuel gum and petroleum varnish that restricts fuel passageways. The most important thing Marine PRO does is liquefy and clear away sticky gum and varnish restrictions so the engine can go back to starting fast and running strong.