Mercury Fuel Additives Review: Do Quickare, Quickleen & Quickstor Really Work?

Nov. 23 2025 Mercury Maintenance By Patrick Pershing

Modern ethanol-blended fuel creates real challenges for boat owners. Water intrusion, phase separation, corrosion, and carbon buildup are all common issues Mercury owners face.

To combat these problems, Mercury Marine developed a 3-step fuel-treatment system designed specifically for outboard engines: Quickare, Quickleen, and Quickstor. At Cope Marine, we recommend this system for nearly every owner of a Mercury outboard because it’s one of the most effective (and inexpensive) ways to protect engine performance and longevity.

Below is an in-depth review of how each product works—and why local boaters in O’Fallon, St. Louis, and Branson West continue to trust them.

Step 1: Clean – Mercury Quickare

A clean fuel system is the foundation of smooth, reliable engine performance—and Mercury Quickare is the additive built for everyday use.

What Quickare Does

Quickare helps prevent:

  • Rust and corrosion inside fuel components

  • Water accumulation from ethanol-blended fuel

  • Varnish and gum deposits

  • Injector clogging and poor atomization

Why It Matters

When your injectors spray an even, fine mist of fuel, your Mercury outboard:

  • Runs smoother

  • Starts easier

  • Burns fuel more efficiently

  • Maintains peak horsepower

For boaters in Missouri and Southern Illinois, where ethanol fuel and humidity create ideal conditions for moisture buildup, Quickare is one of the best preventive steps you can take.

Step 2: Deep Clean – Mercury Quickleen

Quickleen is not a daily-use product—it’s a deep-cleaning formula designed to remove internal deposits that build up over time.

What Quickleen Cleans

  • Carbon buildup on piston rings

  • Carbon deposits on intake and exhaust valves

  • Carbon fouling that shortens spark-plug life

Why It Matters

Carbon buildup is one of the leading causes of:

  • Stuck piston rings

  • Loss of compression

  • Sticky valves

  • Power loss and rough running

By eliminating carbon, Quickleen helps restore performance and extend the life of key components. Boaters who troll frequently or idle long periods benefit greatly from regular Quickleen treatments.

Step 3: Store – Mercury Quickstor

If you store your boat for the winter in O’Fallon, IL, leave it docked at Lake of the Ozarks, or let it sit unused for a few weeks, Quickstor is the protection your engine needs.

What Quickstor Prevents

  • Breakdown of gasoline during long-term storage

  • Formation of gum and varnish

  • Moisture accumulation caused by ethanol fuel

  • Corrosion inside injectors and fuel lines

How to Use It

Add 1 ounce of Quickstor per 5 gallons of fuel, then run the engine long enough to circulate treated fuel through the entire system. This ensures that every fuel component—from the tank to the injectors—is protected.

Why Winterizing with Quickstor Is Critical

In Midwest climates, long idle periods cause untreated fuel to deteriorate quickly. Using Quickstor during winter storage prevents costly spring start-up issues and protects your Mercury outboard for the long haul.

Cope Marine’s Recommendation

For Mercury outboard owners in the St. Louis Metro, Southern Illinois, and Southwest Missouri, this 3-step Mercury additive system is one of the most cost-effective ways to:

  • Improve fuel efficiency

  • Prevent ethanol-related engine issues

  • Extend the life of injectors, pumps, rings, and valves

  • Reduce carbon buildup

  • Protect your engine during winter storage

Whether you run a fishing boat, pontoon, bass boat, or performance tri-toon, these additives provide a level of protection you can see and feel on the water.

Need Mercury Additives or Expert Advice? Visit Cope Marine

Cope Marine stocks the full line of Mercury Quickare, Quickleen, and Quickstor at all of our locations:

O’Fallon, Illinois
St. Louis / Metro East
Branson West, Missouri

Stop in, give us a call, or ask our service team which treatment schedule is best for your boat and your boating habits.