Thanks for the question! It depends on what you’re trying to accomplish by adding Sea Foam.

For cleaning, I like to wait until the tank is low (1/4 -1/8 tank), add the whole 16 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. Do that every 3,000-5,000 miles and you’ll keep your fuel system and critical engine areas clean. (For boats/tractors/anything else, do it at least once per season).

That’s the best way to get the most out of a can of Sea Foam.

If you’re storing a vehicle/fuel/fuel tank, add 1 ounce of Sea Foam per gallon

Good question, Steve. A lawn mower won’t run on straight Sea Foam, but you can use a high concentration of Sea Foam in gas for a good deep clean.

I’d do something like this: run your mower until empty, and add 8 oz of fuel with 4 oz of Sea Foam (a 2:1 ratio of gas to Sea Foam). Then, run it until empty.

Thanks for the question, Kevin. In addition to stabilizing fuel, Sea Foam cleans gum and varnish from the entire fuel system and prevents it from forming. Gum and varnish is often the cause of rough performance or hard starts. Sea Foam will clean it out, helping your generator start and run better.

Thanks for the question, Angela! Yes, you can use Sea Foam Motor Treatment in any gas engine. It’s safe and effective. Just add it to fuel.

Thanks for the question! It is absolutely okay to add it to a tank of fuel and let it sit for a while. It’s made with 100% safe petroleum cleaning and lubricating ingredients that can’t harm parts or components. The Sea Foam will actually help prevent fuel from degrading while it sits, so it’s a good thing to have in the fuel tank of a car that doesn’t get driven often.

I would add it before you drive, though (rather than after you park it). That allows the treated fuel to run through the fuel system. If you add it after you park, the untreated fuel in the fuel lines won’t be protected from degrading.

That said, here’s how I like to use it for cleaning: wait until the tank is low (1/4 -1/8 tank), add the whole 16 oz can, and then drive for at least 10-20 miles before refueling your tank. The high concentration works very well for cleaning fuel residues and deposits. It works better and faster than adding a can to a full tank of fuel.

If you’re going to park your car for a while like you mentioned, you could add 1 oz of Sea Foam to the tank to protect the fuel.