Good question, Garret. The short answer is yes – you can add a full 20 oz bottle of Sea Foam Marine PRO to a full tank of gas. It’ll work to clean the entire fuel system and stabilize fuel.

The longer answer is it depends on what you are using Marine PRO for. If you want to clean fuel residues and deposits, you want to create a high cleaning concentration of Marine PRO. Add a full can to 2-3 gallons of fuel, and run your Seadoo until almost empty before refilling with fresh fuel. If you haven’t used Sea Foam in your Seadoo before or want to clean it up, I’d start with this.

If you’re using it for routine/preventative maintenance or stabilizing fuel, add at least 1 oz per gallon of fuel to every tank.

Good question, Greg. The best way to clean a carb is to create a high cleaning concentration of Marine PRO. 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.

Hope that helps!

Thanks for the question! Marine PRO is safe and effective in your small engines and it’s similar to Sea Foam Motor Treatment in that it cleans fuel residues and varnish and stabilizes fuel. You could use either one.

If you want a formula that’s made for tougher fuel residues and varnish, give High Mileage a try in your small engines. That’s my favorite of the Sea Foam fuel treatments and what I use in just about everything. It stabilizes fuel as well.

Good question, Romeo. Yes, Marine PRO is safe and effective in a gasoline car/truck’s fuel tank. While it’s formulated for marine engines, you could use it in any gasoline engine. That said, if you have a choice between buying that or Sea Foam Motor Treatment (or High Mileage), go with Sea Foam Motor Treatment. If you have some Marine PRO you’re trying to use up, go for it!

Good question, Dan.

It’s safe to add a lot of Marine PRO to your boat’s gas tank. In fact, a high concentration of Marine PRO in fuel does a great job cleaning up fuel residues and deposits that often cause performance problems like rough idle, hard starts, and loss of power.

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 and add 1 ounce of Marine PRO per gallon of fuel. That will prevent fuel from degrading and preserve ignition vapors.

In oil, add 1 ounce of Marine PRO per quart of oil.