This Quicksilver flushing kit hooks up to a hose and lets you run your Mercury or Mariner between 4 and 15 horsepower at idle while you wash salt out of the leg. It matches 2 stroke outboards from 4 to 15 horsepower plus the small 4 stroke 4 5 and 6 horsepower engines. It also covers the 323 cc 8 9.9 and 15 horsepower standard gearcase motors. The kit sits over the gearcase water inlets and feeds mains water straight through the cooling passages. You just keep the revs at idle and let the fresh stuff do the work. It is a smart buy if you run small horsepower gear in Aussie salt water and want to keep the cooling side clear. Use it in the driveway after each session and you help the motor go the distance.

• Suits Mercury/Mariner 4–15 hp outboards
• Compatible with 2-cycle and small 4-stroke models
• Covers 323 cc 8, 9.9 and 15 hp engines
• Fits standard Mercury/Mariner gearcase water inlets
• Allows engine operation at idle during flushing
• Routes mains water into cooling passages
• Ideal for post-trip flushing after saltwater use
• Simple clamp-on kit for home or workshop use
• Helps reduce salt and debris build-up in cooling system
• Supports long-term reliability of small outboards

Q: Can I use this flushing kit with other outboard brands?

No, this kit is specified for Mercury and Mariner outboards only. The sealing shape is made to suit their standard gearcase water inlets from 4 to 15 hp. Using it on other brands may not seal correctly around the intake area. Poor sealing can reduce water flow and limit the effectiveness of the flush.

Q: What engine speed should I use while flushing?

You should only run the engine at idle speed when using this flushing kit. Higher rpm can reduce cooling efficiency because the water supply comes from a garden hose not a full water column. Staying at idle helps keep water pressure and flow consistent. It also avoids unnecessary wear while the boat is on the trailer or in the yard.

Q: How often should I flush my outboard with this kit?

Flush the engine after each run in salt or dirty water. Regular flushing helps clear salt crystals and silt out of the cooling passages. The habit is especially useful for small outboards that spend time at low speed where deposits can build up. Consistent flushing can support long term reliability of the water pump and thermostat areas.

Q: Does this kit replace any internal engine servicing?

No, the flushing kit only helps rinse the external cooling passages. You will still need normal servicing such as gear oil changes, spark plugs and impeller checks at the recommended intervals. Using the kit simply adds an extra layer of care between those services. Treated as part of your routine, it can help reduce corrosion around the cooling galleries.

Fits Mercury/Mariner 4–15 hp 2 cycle outboards. Fits Mercury/Mariner 4/5/6 hp 4-stroke outboards. Fits Mercury/Mariner 8/9.9/15 hp 323 cc outboards with standard gearcase. Kit supports running the engine at idle speed while flushing.