Hi Theodore,

Thanks for the question! Sea Foam works to clean fuel resides and deposits. If that’s what is causing the rough running, it will work to help clear things up as the treated fuel is running through the system. It won’t work “immediately,” but it should clear up within one tank of gas if that’s the problem. If a dirty fuel system isn’t the problem, it won’t help the rough running, but you’ve narrowed down the potential problem and eliminated that one as a potential cause.

Here’s what I’d do: 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. Add it to fuel like this every 3,000 miles or once a year.

If you’re talking about a small engine, use a similar process: add a 1:2 ratio of Sea Foam to gas (such as 8 oz of Sea Foam in 16 oz of fresh gas), and run through the tank of treated fuel.

Hope that helps and let me know if you have any other questions!

Good question, Eugene. Yes, you’ll want to do what you described and let it sit overnight before trying to start it. That will give the Sea Foam a chance to reliquefy fuel gum/varnish that’s formed while it sat.

Here’s an overview, and a detailed step-by-step:

1. Drain the old fuel.
2. Add a 1:2 ratio of Sea Foam to fresh gas.
3. Prime/crank/rope pull to draw the treated fuel into the carburetor.
4. Let it sit overnight – 24 hours minimum – or longer.
5. Once it starts, run it as normal/as you need it and use up that treated fuel. The Sea Foam will continue to clean as it runs.

https://seafoamworks.com/uploads/public/resource-library/2022/07/HOW2_GummedUp-Carb.pdf

Thanks for the question, Russel. Yes, you can add Sea Foam to that tank of gas. It is compatible with those other additives.

To clean up fuel varnish, you’ll want to add a high concentration of Sea Foam to the tank. You can use up to a 1:2 ratio of Sea Foam to gas. If you’ve got a gallon or more already in the tank, I’d add the whole 16 can. If less than a gallon, add up to half a can. After that, start the engine and let it idle for 10 or so minutes to allow the Sea Foam mixture to flow through the carburetor circuits, then shut off the engine.  Let the engine sit and allow it to soak overnight. Idle the engine for 5-10 minutes. Then, whenever you need it next, operate as normal. The Sea Foam will help clean up any varnish in the fuel system.

Hope that helps and let me know if you have any other questions!

Thanks for the question, David. For preventative maintenance, yes, you can add it to a full tank of gas. If you’re using it for cleaning, here’s what I’d do: 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. Add it to fuel like this every 3,000 miles or once a year.

Hope that helps and let me know if there’s anything else!