Water Flushing Systems

Boat Flushing Kits and Systems - Resources & Information

For winterization, Water Flushing Systems are essential to remove saltwater and sand from your motor, as well as preventing debris build-up and corrosion when your boat is not in use. Plus, having a source of cooling water from motor flushers (also known as “outboard ear muffs” or “water flushers”) while servicing your engine on dry land is absolutely necessary for safe maintenance without overheating. 

PartsVu offers a complete selection of Water Flushing Systems from OEM manufacturers and trusted aftermarket suppliers. Whether you need a Yamaha outboard flush kit, Mercury outboard flush adapter, or universal motor flushers, PartsVu has what you need to get the job done. 

Need help servicing your boat and outboard engine? PartsVu regularly publishes helpful how-to guides and other valuable maintenance information to help boaters properly service their boats and engines. Browse our outboard maintenance blog for a wide range of relevant topics and see the FAQ section below, covering everything you need to know about maintaining your boat in confidence.

Water Flushing Systems FAQ

What are water flushing systems for winterizing boats used for?

Water flushing systems are used for winterzation boats to help remove any remaining water from the boat's engine and plumbing systems. These systems typically consist of a hose that is attached to the boat's water intake and a motor that is used to force water through the engine and plumbing. The water is then flushed out through the boat's exhaust, which helps to prevent the water from freezing and causing damage during the winter. By using a water flushing system, you can help to ensure that your boat's engine and plumbing are free of water, which can help to protect your boat from the damaging effects of freezing temperatures.

What should I know about Water Flushing Systems?

Here’s some info you need to know about Water Flushing Systems:

• Flushing a boat motor should be a mandatory part of your engine maintenance every time you finish using your outboard motor. Whether you boat regularly or a few times per season, salt water and other contaminants can erode the cooling passages, leading to severe engine damage. Therefore, it’s important to learn how to flush boat engine (see instructions below). 
• An outboard motor flusher made by an OEM manufacturer typically provides a better fit than aftermarket engine flush kits. For example, when flushing Yamaha outboard motors, a Yamaha flush kit typically has a Yamaha flush adapter (or Yamaha outboard flush hose connector) that creates a watertight fit. If there’s an issue with your Yamaha engine that you’re hoping to be covered by a warranty, using aftermarket flushers
• Wondering how long to flush outboard engine? In most cases, it only takes 5 minutes of flushing, which can be done at the marina once your boat is loaded on to a trailer or when you’ve tilted the outboard(s) from the water. 
• Using an engine flush solution (or “de-scaling solution”) like Starbrite Salt Off is typically a good idea if you’ve noticed the weep hole not draining as well as it once did; or, if you’re not entirely confident that the freshwater you’ve used to flush won’t leave its own mineral deposits behind when it dries (such as calcium).
• Looking for in-depth articles about how to flush your engine, flushing for winterization, and other related topics? If so, the following blogs can help you learn everything you need to know about Outboard Engine and Motor Flushers for Boats:
• Marine Corrosion – Corrosion Types and What to Do About Them
• Yamaha Corrosion Prevention – Protect Your Engine
• How to Stop Marine Rust & Corrosion
• Winterizing Mercury Outboard Motor—Mercury Marine Essential Maintenance
• Winterizing Outboard Motor—Yamaha Essential Maintenance
• Boat Winterization in South Texas?
• How to Winterize a MerCruiser Sterndrive

How do I flush my Mercury outboard engine?

It’s important to thoroughly flush your engine to remove any salt buildup if you are a saltwater boater, or general mud and grime if you are a freshwater boater. Failure to remove this debris can cause or contribute to corrosion in the engine. If you’re a saltwater boater, salt crystals in the lower unit can cause a great deal of damage.

Flush with the Engine Not Running (using a hose port)

You’ll need:

• Garden hose
• Water supply

If your engine has a hose adapter, simply screw the hose into the port, turn on the water and let the water run for about 5 minutes.

Finally, tilt the engine all the way up, then trim it all of the way down to make sure every drop of water drains from the engine.

**Caution** Do not run the engine when flushing while using a hose port. This method is solely designed for flushing while your engine is entirely off.

How do I go about freshwater flushing my Yamaha outboard?

Use the built-in flush attachment. This is a great procedure to follow, especially if you can’t remove your boat from the water, or if your outboard has dual water inlets and you don’t have the special adapter. Simply connect a garden hose to the inlet side of your non-running outboard’s built-in flush attachment, turn the spigot on full blast, and let the hose’s water pressure do the work. Let the water run for 15 minutes to ensure it fully circulates through the entire cooling system several times. If your boat’s out of the water, like on a trailer or a lift, the freshwater will also trickle down and adequately clean the water pump and the lower unit’s cooling water passages.

The flush muff method. This is the most common and often-used freshwater flushing method. Simply connect a garden hose to clean fresh water on one end and a Yamaha Outboard Engine and Motor Flusher attachment, which slides around the Yamaha lower unit to provide water to both sides of the raw water inlet, to the other end. Turn on the water until you see water squirting out the sides of the flush muff, then start your outboard in neutral. Set the outboard to no more than a fast idle (900-RPM max) and allow to run for 15 minutes in neutral. Increase hose water pressure enough to maintain a bit of squirting out from under the flush muffs at all times while the outboard is running. This helps ensure it gets fed enough cooling water.

Is winterizing my outboard important?

While it’s always a bit more fun to pull out your boat than to put it away, properly winterizing your outboard engine should be mandatory for all experienced boaters. Winterizing helps avoid engine damage and will facilitate a smoother start to the beginning of next season - after all, no one wants to wait to get back on the water!

There are several important steps you should take when storing your MerCruiser outboard lower unit to ensure that it’s properly winterized.

1. Flush Your Engine - Thoroughly flush your MerCruiser engine to remove any salt buildup if you are a saltwater boater, or accumulated mud and grime if you are a freshwater boater. Failure to remove this debris from your MerCruiser lower unit leads to corrosion in the engine. And if you’re a saltwater boater, leftover salt crystals in the lower unit can act like sandpaper to your internal engine components.
2. Stabilize Your Fuel System - Fuel starts to go bad within 30 days of sitting in your fuel system. It is vital to use a fuel stabilizer when your boat will be sitting unused for more than two or three months. Adding the amount of fuel stabilizer directed on the product’s packaging to your fuel—for instance, 1 ounce of Mercury Quickstor Fuel Stabilizer for every 5 gallons of marine fuel ensures proper winterization for more than 3 months. 
3. Fog Your Engine - Fogging oil is a wax-based oil that coats the engine to prevent corrosion.
4. Change Out the Lower Unit Oil - It’s recommended by marine mechanics to change your gear lube before storage to make sure that there is no water in the lower unit’s oil. Any water in the oil could freeze, expand, and crack your lower unit. Additionally, old oil is more likely to gum up oil passages and corrode components due to changes in its chemical composition through regular use. Last, consult your owners manual for which oil is appropriate for your engine.
5. Disconnect Your Battery - Disconnect your battery and spray CRC Marine Battery Terminal Cleaner on your battery terminals.

Do you need to winterize boat if stored inside?

Whether or not you need to winterize your boat if it is stored inside depends on a number of factors, such as the temperature inside the storage area and the type of boat you have. In general, it is always a good idea to take steps to protect your boat from the cold, even if it is stored inside. This can help to prevent damage to the boat's engine and other systems, and can also help to prevent the growth of mold and mildew. If you are not sure whether your boat needs to be winterized, it is always best to consult with a boat mechanic or other expert who can provide you with guidance on the best way to protect your boat during the winter.