Great question, Neal. There’s two things I’d think about when considering fuel that sits for a while. First, you’ll want to think about cleaning up any fuel varnish that formed while the fuel sat. Second, you’ll want to think about preventing varnish from forming during future periods of inactivity, as well as preserving the fuel’s ignition vapors.

A tank of fuel that sat for three months will still be just fine to run.

I’d take two simple steps:

• First, especially if you’ve never done it before, run a strong cleaning concentration of Sea Foam High Mileage through your Sienna. That will clean up and fuel residues and deposits throughout the whole fuel system. It’s a great thing to do in any vehicle. A quarter tank is actually a perfect time to add Sea Foam. Here’s what I’d do: add an entire 16 oz can of Sea Foam High Mileage to your fuel tank, drive until almost empty (just don’t run out of gas), and then refill your tank. The high cleaning concentration will work much better and faster than adding Sea Foam to a full tank.
• Second, you can protect the fuel that sits in the tank by adding a can of Sea Foam High Mileage (or Motor Treatment) to every tank of fuel. Just add it before you fill up. That will help prevent gum and varnish from forming and prevent the fuel from degrading.

Thanks for the question, Braden!

Sea Foam can be added to one-year-old gasoline, but it cannot restore fuel that has already degraded.

If the fuel still appears to be in good condition, Sea Foam can help stabilize it against further degradation and dissolve any gum and varnish that may have started to form. However, with fuel that’s already a year old, fresh gasoline is the safest choice, especially for a generator that you need to be reliable.

For future storage, add at least 1 ounce of Sea Foam per gallon of fresh fuel before storing, and run the generator long enough to draw the treated fuel throughout the fuel system. Sea Foam will help stabilize stored fuel for up to two years.

Thanks for the question! Yes, you can use Sea Foam Motor Treatment in any gasoline or diesel fuel, including ethanol free gasoline. Just follow the directions on the can.

Hi Harry ,

Thanks for the question! Yes, you can use Sea Foam in a Stihl chainsaw, and any other gas or diesel engine.

For preventative maintenance, add 1 ounce of Sea Foam per gallon of fuel to every tank. That will keep fuel from degrading and prevent gum and varnish from forming. For cleaning the entire fuel system, use a high concentration of Sea Foam – up to a 1:2 ratio of Sea Foam to gas. If you’re experiencing problems with it (or want to just do a really good cleaning), I’d add 4 oz of Sea Foam to 8 oz of gasoline and run it for about ten minutes, shut it off, let it sit overnight, and then run it for a few minutes again the next day. That will do a great job cleaning up any fuel gum or varnish that’s formed anywhere in the fuel system. Gum and varnish is a very common cause of problems in a small engine like that.