Fuel & Additives

  1. Yamaha Ring Free Plus Fuel Additive - ACC-RNGFR-PL-32

    $70.99
    1
  2. ValvTect BioGuard Diesel Plus 6 Fuel Treatment - 32 oz - BGDP632

    $48.99
    0
  3. Seafoam Motor Treatment and Spray Combo - SF-SS

    $29.99
  4. Sta-Bil Diesel Stabilizer - 32 oz - 22254

    $28.99
    0
  5. MDR Ethanol Gasoline E-Zorb Water Remover - 16 oz - MDR-574

    $27.99
    0
  6. Star Brite Diesel Water Absorber - 084616

    $25.55
  7. MDR Gasoline Water Zorb Water Absorber - 16 oz - MDR-567

    $24.99
    0
  8. ValvTect Diesel Guard Supreme Plus High Performance Diesel Additive - DFMS32

    $24.99
    1
  9. Yamaha Ring Free Plus Fuel Additive - ACC-RNGFR-PL-12

    $24.99
    0
  10. MDR Diesel Fuel Water Zorb Water Absorber - 16 oz - MDR-559

    $23.99
    0
  11. Hammonds BioborMD Diesel Fuel Additive - BBMD16EZ01US

    $21.99
    0
  12. Seafoam Ultimate Oil Stabilizer - OS32

    $21.93
  13. Hammonds BioborJF Diesel Fuel Additive

    $18.82 - $28.99
    0
  14. Star brite Star Tron Ring Cleaner - 95616

    $18.14
    0
  15. Seafoam Marine PRO Engine Fuel Treatment - MP20

    $17.62
  16. Star brite Star Tron Diesel Additive

    $17.43 - $46.99
    1
  17. Mercury Quickleen Gasoline Engine Treatment - 12 oz - 8M0047931

    $16.99
    1
  18. Seafoam High Mileage Motor Treatment - HM16

    $16.58
  19. Star brite Star Tron Enzyme Fuel Treatment for Gasoline

    $14.33 - $36.99
    1
  20. Mercury Quickare Gasoline Fuel Treatment - 12 oz - 8M0047930

    $13.99
    0
  21. Seafoam Motor Treatment

    $13.69 - $94.99
  22. Star Brite Star Tron Enzyme Fuel Treatment - Diesel Automotive Formula - 14408

    $12.31
  23. Star Brite EZ Store EZ Start Diesel Storage Additive - 084408

    $12.01
  24. 7% off

    BRP Carburetor and Choke Cleaner - 777191

    $12.99
    $11.99
    0
  25. Sta-Bil 360 Marine Formula Ethanol Gasoline Treatment

    $10.84 - $27.99
    0
  26. BRP 2+4 Gasoline Fuel Conditioner and Stabilizer - 8 oz - 766216

    $9.99
    0
  27. Star Brite Star Tron Stabilizer+ Fuel Storage

    $8.75 - $14.76
  28. Seafoam Fuel Injector Cleaner and Upper Cylinder Lubricant - IC5

    $8.27
  29. TruFuel 100% Ethanol-Free 4-Cycle Fuel

    $7.99 - $26.99
    0
  30. Star brite EZ-to-Store EZ-to-Start Gasoline Stabilizer

    $7.99 - $21.99
    0
  31. Star Brite Star Tron Enzyme Fuel Treatment - Small Engine Formula - 14301

    $6.84
  32. 15% off

    Liqui Moly Marine Super Diesel Additive

    $8.00
    $6.80
    0
  33. Star brite Star Tron Fuel System & Injector Cleaner - 96604

    $6.68
    0
  34. 14% off

    Sta-Bil Gasoline Fuel Stabilizer

    $6.99 - $19.99
    $5.99 - $19.99
    0
  35. 24% off

    Liqui Moly Marine 4T Additive Shooter - 25102

    $7.41
    $5.56
    0
  36. 25% off

    Liqui Moly Marine Gasoline Stabilizer Shooter - 25100

    $5.00
    $3.75
    0
  37. 30% off

    ValvTect Marine Gasoline Additive

    $5.00 - $27.99
    $3.49 - $27.99
    0

About Fuel & Additives

What are fuel additives & engine treatments?

One of the biggest problems with boating fuel and the need for engine treatments are interactions with polymer components in the boat's fuel system and water issues.
Being out on the water all day gives your boat excessive exposure to water, and that will play havoc with many of your systems.
Water helps facilitate corrosion, as well as the physical properties of water means that with excessive heat and cold, water can expand and get into all sorts of nooks and crannies of your motors and mechanical parts.

Engine treatments are an important part of eliminating this with proper lubrication, fuel stabilization, and winterization are a must for marine engines.
Otherwise, over time, water can begin to promote oxidation and even pitting throughout your engines.
Organic material might also propagate, which can cause blockages, as well as bad fuel which will ruin your engines.

Fuel additives are extremely effective at solving these problems.
Which is why Defender offers a wide variety of marine-specific additives to keep your boat running smoothly.

Types of fuel additives & engine treatments

  • Water absorbents: Petroleum products and water do not mix. At least they don't mix well. Introducing water absorbents to your fuel will help absorb water from fuel and allow it to be safely eliminated.
  • Detergents: Keeping your fuel system clean and preventing the buildup of carbon are important engine treatments for keeping fuel lines and filters open and flowing well. Buildup of debris, carbon deposits, and fuel soluble materials can severely shorten the life of your motor if left unchecked. Detergents are especially important diesel treatment.
  • Fuel stabilizers: If your watercraft is going to sit for long periods of time without use, stabilizers, such as fogging oil, provide a protective layer for the fuel sitting in a gas tank. Often a hydrocarbon, such as methyl alcohol, which bonds with water, yet still remains combustible, fuel stabilizers are good fuel additives for diesel treatments and a proper way to ensure that the remaining fuel left in your tank is still good when you hit the water next season.
  • Biocides: How can anything live in fuel? Water is a natural environment for nearly all life, and the presence of water in your fuel still provides a place for microbes to live, feed, reproduce, and die. Biocides kill bacteria and fungus to rid fuel system of their waste and deposits, which will ruin your filters, connections, and eventually your engines.