Best Marine Fuel Injector Cleaner for Boats and Watercraft

#1 · Best Overall

1. STA-BIL 360 Marine 8 oz

• Weight: 8.6 oz

Best for: In-Season Marine Protection.

Why it ranks #1: Its marine formula cleans injectors, lines, and fuel pumps, and lists water, gum, varnish, and corrosion protection for in-season use.

PEA additives clean fuel injectors, lines, and fuel pumps while the formula removes water, gum, and varnish. That combination gives boat owners a treatment aimed at both deposits and moisture-related fuel-system concerns, with corrosion protection for internal parts during in-season use in marine engines and other water-sport engines.

The whole-system cleaning claim reaches injectors, lines, and fuel pumps, so the treatment addresses several fuel-system areas rather than injectors alone. Its water-removal and corrosion-protection features speak to moisture exposure in marine use, while removal of gum and varnish targets accumulated deposits. The listed use includes boats, jet skis, and other water-sport engines. Together, these features suit owners looking for ongoing in-season cleaning and protection, rather than a cleaner described only for occasional carbon removal.

Skip it if you need a stated dose for measuring each treatment; STA-BIL 360 Marine 32 oz lists a rate of 1 oz per 10 gallons.

Choose this for in-season marine care when cleaning multiple fuel-system components and addressing moisture are priorities. Its listed use covers boats and jet skis; buyers who require a stated dose should consider that the supplied 8 oz details give none.

Listed on Amazon as: STA-BIL 360 Marine Fuel System Treatment, 8 oz

#2 · Best Dose Clarity

2. Quicksilver Quickleen

• Weight: 0.27 g
• Volume: 12 fluid oz
• Size: 12 Fl Oz (Pack of 1)

Best for: Frequent-Tank Deposit Cleaner.

Why it ranks #2: The gasoline and ethanol-blend cleaner targets carbon deposits across engine components, with a stated rate of one ounce per five gallons.

A one-ounce dose treats five gallons of gasoline, and Quicksilver Quickleen can be used at every tank fill-up. That specific rate supports repeat-treatment planning for gasoline marine engines, while its listed cleaning targets span carbon deposits in injectors, carburetors, valves, spark plugs, piston crowns, and cylinder heads.

The stated five-gallon treatment rate makes dosing straightforward to scale with a tank fill, and the every-fill-up use guidance supports a regular maintenance routine. Quickleen is listed for all grades of gasoline and ethanol-blend fuel, giving it broad fuel compatibility within that scope. Its carbon-deposit targets extend from injectors and carburetors to spark plugs and cylinder heads, while the product also claims to prevent engine knocking and piston seize-up.

Skip it if you need stated stored-fuel protection; Sea Foam Marine PRO lists fuel stabilization for boats and other marine engines.

Choose Quickleen if you want a stated dose for frequent gasoline-tank treatment and broad carbon-deposit coverage. Its stated compatibility includes ethanol blends; buyers seeking fuel stabilization for storage should look for that claim explicitly.

Listed on Amazon as: Quicksilver Quickleen Engine and Fuel System Cleaner

#3 · Best OEM Formula

3. Mercury Quickleen

• Size: RM

Best for: Seasonal Watercraft Carbon Cleaner.

Why it ranks #3: Mercury Marine specifies this watercraft cleaner for occasional seasonal use; it removes carbon deposits and uses one ounce per five gallons.

Mercury Quickleen removes carbon deposits from components ranging from injectors and carburetors to spark plugs and cylinder heads, at one ounce per five gallons. That occasional-use seasonal guidance gives watercraft owners a defined dose for broad internal deposit cleaning without presenting the product as a fuel stabilizer.

The one-ounce-per-five-gallons rate makes dosing clear, while the recommendation to use it occasionally throughout the season distinguishes it from an every-fill-up routine. Its carbon-removal targets include injectors, carburetors, intake valves, spark plugs, piston crowns, and cylinder heads. The listing also claims prevention of engine knocking and piston seize-up. It explicitly says the formula does not contain fuel stabilizers, so storage fuel breakdown and oxidation require a separate product according to the supplied details.

Skip it if you need fuel stabilization in the same treatment; Sea Foam Marine PRO lists stored-fuel stabilization for marine engines.

This suits watercraft owners seeking occasional seasonal carbon cleaning with a stated dose and Mercury Marine OEM specifications. It is not a stand-alone stored-fuel stabilizer, so plan separately for fuel breakdown and oxidation protection.

Listed on Amazon as: Mercury 8M0047931 Quickleen Engine & Fuel System Cleaner, 12 oz

#4 · Best Storage Support

4. Sea Foam Marine PRO

• Weight: 4.45 lb

Best for: Marine Storage and Deposit Care.

Why it ranks #4: This marine treatment works through injectors and carburetors, helps remove fuel residues, and also helps stored fuel resist evaporation.

Sea Foam Marine PRO combines deposit removal through injectors and carburetors with fuel stabilization for boats, jet skis, and other marine engines. That dual role lets owners address fuel-passage and engine-area residues while also preparing stored fuel to resist evaporation and preserve ignition vapors.

The treatment works through both fuel injectors and carburetors, with listed deposit targets including fuel passageways, intake valves, pistons, and chamber areas. That breadth makes it relevant to owners seeking more than injector cleaning alone. For storage, its listed stabilizing action helps fuel resist evaporation, preserve ignition vapors, and prevent gum and varnish formation. The pack contains three 20 oz bottles, a supply format that suits owners planning repeated marine maintenance or storage treatment.

Skip it if you need a stated per-gallon dose; Mercury Quickleen specifies one ounce for five gallons of gasoline.

Choose Marine PRO for boat or jet-ski owners who want deposit treatment alongside listed stored-fuel stabilization. Its multi-bottle pack supports planned use, but the supplied details do not provide a per-gallon dosing rate.

Listed on Amazon as: Sea Foam Marine PRO Fuel System Treatment, 20 oz, Pack of 3

#5

5. STA-BIL 360 Marine 32 oz

• Weight: 1.9 lb
• Volume: 139 cubic in
• Size: 1 Count (Pack of 1)

Best for: Large-Bottle In-Season Protection.

Why it ranks #5: It shares the 8-ounce version’s marine cleaning and corrosion-protection claims, with directions stating one ounce treats up to ten gallons.

The 32 oz STA-BIL 360 Marine treatment cleans injectors, lines, and fuel pumps while removing water, gum, and varnish. Its listed rate of one ounce per 10 gallons and bottle-side measurement marks help owners plan larger-volume in-season fuel-system care with corrosion protection.

PEA additives support the stated cleaning of injectors, lines, and fuel pumps, while water, gum, and varnish removal addresses several listed fuel-system concerns. The formula also provides rust and corrosion protection for internal parts during in-season use. Directions give a one-ounce-per-10-gallon rate and describe small- and large-quantity measuring methods using the bottle caps and side markings. That combination links broad cleaning claims to practical measurement for marine fuel volumes.

Skip it if you need an explicitly stated storage-protection feature; Sea Foam Marine PRO lists fuel stabilization for stored marine fuel.

Choose this for in-season marine care when a larger bottle, stated dosing, and cleaning across multiple fuel-system parts matter. Its supplied directions focus on in-season treatment, so storage-specific stabilization may require a different choice.

Listed on Amazon as: STA-BIL 360 Marine Fuel System Treatment, 32 oz

#6

6. STAR BRITE Star Tron Cleaner

• Weight: 4.8 oz
• Volume: 4 fluid oz
• Size: 1 Count (Pack of 1)

Best for: Measured Marine Injector Care.

Why it ranks #6: The concentrated injector and fuel-system cleaner treats 40 gallons per four-ounce bottle, with directions calling for use every four to five tanks.

A concentrated four-ounce bottle treats 40 gallons, with directions calling for one fluid ounce per 10 gallons and treatment every four to five tanks or as needed. Those explicit instructions help marine owners plan measured, intermittent fuel-system and injector cleaning instead of guessing at a dose.

The stated rate of one fluid ounce per 10 gallons and 40-gallon total treatment capacity make this small bottle easy to allocate across known fuel volumes. Directions recommend use every four to five tanks or as needed, providing a defined maintenance interval. The listing identifies the liquid as concentrated and as a fuel-system and injector cleaner. Separate Star Tron information mentions enzyme treatment and ethanol concerns, but those claims are not established as features of this cleaner itself.

Skip it if you need named deposit targets or water-removal claims; STA-BIL 360 Marine 8 oz lists removal of water, gum, and varnish.

Choose this for measured, periodic fuel-system and injector cleaning when a clearly stated dose and interval matter. The supplied details do not specify particular deposits removed, so buyers seeking that cleaning detail should weigh the listing carefully.

Listed on Amazon as: STAR BRITE 096604 Star Tron Fuel System and Injector Cleaner – 4 oz.

#7

7. STA-BIL Marine Tune-Up

• Weight: 7.5 oz

Best for: Storage-Focused Marine Treatment.

Why it ranks #7: Its marine-specific listing says it protects internal components during storage, but supplies little detail about injector cleaning or treatment directions.

Protection for internal components during storage is the clearest stated feature of STA-BIL Marine Tune-Up Fuel Treatment. That makes it a candidate for boat owners prioritizing storage protection, although the supplied product details do not specify its cleaning targets, treatment rate, or engine compatibility beyond its marine product name.

The verified storage-protection claim gives this treatment a defined role for owners preparing an engine for storage. Its 8 oz size and compact listed dimensions provide basic handling information, but the supplied details do not explain a dose or name particular deposits it cleans. That makes it harder to plan use or compare cleaning coverage from the listing alone. Buyers can identify the storage-protection purpose, but should not assume a specific injector-cleaning method or broader fuel-system claims from the title alone.

Skip it if you need documented injector-cleaning targets or dosing directions; Quicksilver Quickleen specifies both its deposit targets and rate.

This suits a marine owner whose main listed priority is protecting internal components during storage. It is a less informative choice when you need documented injector-cleaning coverage, a treatment rate, or clear operating directions in the supplied product details.

Listed on Amazon as: STA-BIL Marine Tune-Up Fuel Treatment, 8 oz

#8

8. Seafoam IC5 Cleaner

• Weight: 5.6 oz

Best for: Gasoline Injector Restoration.

Why it ranks #8: This gasoline-injection cleaner targets injector spray patterns and lost power, but its supplied description does not establish marine-specific protection.

Seafoam IC5 is specifically formulated to clean injectors in gasoline fuel-injected engines, with the stated aim of restoring injector spray patterns. That focus connects cleaning to recovering lost engine power and fuel economy attributed to dirty injectors, making it a narrowly targeted option rather than a broadly described marine fuel-system treatment.

The gasoline fuel-injection limitation helps define compatibility, while the injector-cleaning focus suits owners concerned about dirty injectors rather than deposits across named engine components. Its description links cleaning to restored spray patterns, which in turn is presented as a way to recover lost power and fuel economy caused by dirty injectors. No dose, tank capacity, or marine-specific protection feature is supplied, so the listing supports a focused injector-cleaning role, not a detailed maintenance schedule.

Skip it if you need a stated dose and marine storage care; Sea Foam Marine PRO lists stabilization for boats and other marine engines.

This fits an owner of a gasoline fuel-injected engine focused on injector spray patterns and performance losses attributed to dirty injectors. The supplied details do not establish a dose or marine-specific storage protection, so those needs call for another option.

Listed on Amazon as: Seafoam IC5 Fuel Injector Cleaner

#9

9. Red Line SI-1 15 oz

• Weight: 16 oz
• Volume: 443 ml
• Size: 15 Fl Oz (Pack of 1)

Best for: Broad Deposit-Cleaning Treatment.

Why it ranks #9: The concentrated cleaner addresses injectors and other deposits, but its directions describe a neglected vehicle tank rather than marine use.

Red Line SI-1 combines high- and low-temperature detergents to clean injectors, carburetors, valves, and combustion-chamber deposits. That broad set of targets gives owners looking beyond injector-only cleaning a single fuel treatment that also claims corrosion prevention and enhanced gasoline stability.

Its detergent blend is described as cleaning deposits across injectors, carburetors, valves, and combustion chambers, so the stated scope reaches more than fuel injectors. Corrosion prevention and enhanced gasoline stability add fuel-system and fuel-quality aims alongside cleaning. The listing also identifies a synthetic upper-cylinder lubricant and says the cleaner handles all forms of injectors, including GDI. Directions call for one bottle per tank for most effective treatment of a neglected vehicle, a substantial treatment approach to consider for marine use.

Skip it if you need an explicitly marine-labeled formula; Mercury Quickleen is identified for watercraft and specifies occasional seasonal use.

This fits owners prioritizing broad deposit cleaning and corrosion prevention, including injector types such as GDI. Its directions mention a full bottle for a neglected vehicle, so consider that treatment approach when choosing it for a marine engine.

Listed on Amazon as: Red Line 60103 SI-1 Complete Fuel System Cleaner – 15 Ounce- Fuel Injector Cleaner and Carburetor Cleaner for Corrosion Prevention and Injector, Valve, and Combustion Chamber Deposit Removal

#10

10. Red Line SI-1 2-Pack

• Volume: 15 fluid oz
• Size: 15 Fl Oz (Pack of 2)

Best for: Two-Bottle Broad-System Cleaning.

Why it ranks #10: This two-bottle automotive fuel-system cleaner targets injectors and deposits, but the supplied facts do not specify marine compatibility.

This two-pack supplies two 15-ounce bottles of Red Line SI-1, whose concentrated detergent blend targets injectors, carburetors, valves, and combustion-chamber deposits. The multi-bottle format suits owners planning more than one treatment, while the formula also claims corrosion prevention and improved gasoline stability.

The high- and low-temperature detergent blend is described as cleaning deposits across injectors, carburetors, valves, and combustion chambers, giving the treatment broad stated coverage. Corrosion prevention and enhanced gasoline stability add protection aims beyond deposit removal. The two 15-ounce bottles provide multiple units for planned treatments, and supplied facts say it cleans all forms of injectors, including GDI, and contains synthetic upper-cylinder lubricant. The listing does not specify a marine-only application or a treatment rate.

Skip it if you need a stated marine dose; Mercury Quickleen identifies watercraft use and specifies one ounce per five gallons.

This suits owners wanting multiple treatments of a broad fuel-system cleaner with stated corrosion-prevention and stability aims. The supplied details do not give marine-specific directions or dosing, so confirm those needs before choosing it for a boat.

Listed on Amazon as: Red Line 60103 SI-1 Complete Fuel System Cleaner, Cleans and Prevents Corrosion in Fuel Systems, Cleans Injectors, Carburetors, Valve and Combustion Chamber Deposits – 15 Ounce (2 Pack)