Mercury 8M0047931 Quickleen Engine & Fuel System Cleaner, 12 oz

Mercury 8M0047931 Quickleen Engine and Fuel System Cleaner is a dedicated treatment formulated to tackle stubborn internal deposits. Carbon accumulation inside an engine can degrade performance and lead to mechanical strain. This fluid targets multiple internal surfaces, helping engine owners maintain proper fuel flow and combustion health across the operating season.

The formula works across the fuel and ignition path to remove carbon deposits from carburetors, fuel injectors, intake valves, and spark plugs, as well as piston crowns and cylinder heads. By keeping these critical components clean, it actively helps prevent engine knocking and piston seize-up. Because it is produced by Mercury Marine to original equipment manufacturer specifications, it matches precise standards backed by decades of engineering, testing, and manufacturing experience.

Using this cleaner is straightforward and efficient due to its high concentration. It is intended for occasional use throughout the season, requiring only 1 ounce to treat 5 gallons of gasoline. This means a single 12-ounce bottle provides enough treatment capacity for up to 60 gallons of fuel.

One key limitation to keep in mind is that this formula does not contain fuel stabilizers. If you are looking to prevent fuel breakdown and oxidation during storage or regular use, Mercury recommends pairing this cleaner with Mercury Quickare, as Quickleen solely focuses on deposit removal.

Verdict: Mercury Quickleen is an ideal fuel additive for owners who need targeted carbon deposit removal to prevent knocking and piston seize-up. It is best suited for seasonal upkeep in engines running standard gasoline where a stabilizer is not required or is added separately.

A great fit if you:

• Need to clean carbon from injectors, carburetors, valves, or spark plugs
• Want an additive to help prevent engine knocking and piston seize-up
• Prefer products built to original equipment manufacturer specifications
• Want a concentrated cleaner where 1 ounce treats 5 gallons of gas

Consider something else if you:

• Need a fuel stabilizer to prevent fuel oxidation and breakdown
• Want an all-in-one cleaner and stabilizer in a single bottle

What is the mixing ratio for this cleaner?
Just 1 ounce of Quickleen treats 5 gallons of gasoline.

Does this product stabilize fuel?
No, it does not contain fuel stabilizers. To prevent fuel breakdown and oxidation, Mercury recommends using Mercury Quickare.

What parts of the engine does it clean?
It removes carbon deposits from carburetors, injectors, intake valves, spark plugs, piston crowns, and cylinder heads.