What does this stabilizer actually do?

It slows fuel aging and oxidation and protects the fuel system from corrosion, mainly for long-term storage. It does not clean deposits or boost octane.

Can I use it in a diesel engine?

No. It is formulated for gasoline only. Diesel boats need a diesel-specific stabilizer.

Follow the treat rate on the bottle and match it to your tank size. Add it to fresh fuel and run the engine briefly so treated fuel reaches the system.

Is it the same as a fuel system cleaner?

No. A cleaner removes deposits; this product stabilizes fuel and prevents corrosion. Many owners use both.

How does it compare with Sta-Bil Marine?

Both stabilize gasoline and fight corrosion for storage. Liqui Moly uses an organic formula and comes in a one-liter bottle; Sta-Bil Marine is widely available in smaller bottles with a measuring chamber.

Will it fix fuel that has already gone bad?

It is best added to fresh fuel before storage. It slows deterioration but does not restore stale fuel, so drain and refill if fuel is already spoiled.