How to use a high cleaning concentration of Sea Foam in fuel


When cleaning a gasoline or diesel fuel system, it’s safe to add higher concentrations of Sea Foam Motor Treatment to fuel. In fact, the more Sea Foam you add to fuel, the greater the cleaning solvency.  As stated at the end of the video, “Never be bashful when it comes to adding Sea Foam to fuel.”


Ways to apply higher cleaning concentrations:

  • One way is to add Sea Foam Motor treatment when a fuel tank is low. For example, adding a full can (16 ounces) to 8 gallons of fuel is a 2 ounce per gallon ratio. Adding a full can to 4 gallons is a 4 ounce per gallon ratio, …
  • If you think 2 or 4 ounces per gallon are high dosages, consider canister cleaning methods by professional mechanics that use 50/50 ratios in gasoline or 100% straight Sea Foam when cleaning diesel injectors through primary filter cavities or fuel rails.
  • A Sea Foam Spray treatment through any auto gasoline air intake is adding a full can to clean intake valves and chamber areas in a matter of 4 minutes.
  • High concentrations of Sea Foam can also be applied using small accessory fuel tank mixtures, by priming gasoline fuel filters with straight Sea Foam, and fogging cylinder cavities with Sea Foam Spray during storage periods.


If you’ve never used a borescope to view the inside of a healthy engine, consider that the amount of unburned hydrocarbon deposits showing in the photo immediately below is typical for most combustion chambers.

Here’s a chamber view of a Mercury Optimax 2-stroke direct-injection outboard with a long term commitment to using Sea Foam and Sea Foam Spray to clean, lubricate, and protect the entire fuel system:

ST chamber SF copy

Here’s a lower cylinder view from the same Mercury Optimax outboard. Notice the absence of compression ring stains on walls (rust stains are typical) and no hydrocarbon deposits whatsoever:

ST cylinder SF copy


Remember, Sea Foam Motor Treatment only contains petroleum-based ingredients and is always safe to use in all types of gasoline and diesel engine fuels.  It does NOT contain harsh detergent or abrasive chemicals.  Sea Foam in your fuel is always cleaning, lubricating and protecting your entire fuel system!

Watch The
How 2 Video

In this video Brian shows how to use a high dosage of Sea Foam Motor Treatment for cleaning in fuel.

You can add A LOT of Sea Foam to fuel. We get a lot of questions about how much Sea Foam Motor Treatment to use when cleaning all types of gasoline and diesel fuel systems. If you think 2 ounces per gallon is a high dosage, consider cleaning methods by professional mechanics that use 50/50 in gasoline and 100% straight Sea Foam when cleaning diesel injectors. Watch Brian cover the subject, demonstrate a high cleaning concentration at high engine RPM, then show the inside of the same engine using a borescope camera.

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