How to Operate the Honda WD20 Deluxe Water Pump

honda 20 water pump

Ready to put your Honda WD20 deluxe water pump to work? Here’s everything you need to know about using your pump from setting up the suction hose to stopping the engine.

Pre-Operation Safety:

Never use this pump to move corrosive or flammable liquids. Saltwater, chemical solutions, and caustic liquids should also be avoided to prevent pump damage. Keep the unit at least three feet (one meter) away from buildings to prevent carbon monoxide build-up, and always operate the unit on a level surface.

Suction hose:

Always use a reinforced wall or wire braided hose to prevent collapse from suction pressure. Use the shortest hose possible to reduce priming times. Secure the hose to the pump housing with a hose band, and install a strainer on the hose opening to prevent rocks and debris from entering the pump.

Discharge hose:

If using a fabric hose, secure it to the discharge opening with a hose band. A shorter hose will decrease fluid friction, improving flow rates and efficiency.


The Oil Alert System will automatically shut off the engine if the oil level is too low. When this happens, the alert lamp, located next to the engine switch, will light. To prevent these shutdowns, check the oil level before each use: remove the filler cap/dipstick, wipe it clean, put it back into the opening without screwing it in and then check the level on the dipstick. Add additional oil as needed.  The motor is built to use oil that meets service certification SE or SF. 10W40 is recommended, but 10W30 can be used at temperatures between -4 to 86°F (-20 to 30°C) and both 20W40 and 20W50 can be used at temperatures above 14°F (-10°C.)


The motor should use fresh unleaded fuel with an octane rating of 86 or higher. Pinging is normal under heavy load; if the engine pings under normal load, try using a different brand of gasoline. Never use fuel containing more than 10% ethanol (E10) or 5% methanol. The tank on the WD20 holds 0.66 gallons (2.5 liters.)

Air cleaner:

Before each use, inspect the filter, located above the starter grip, and clean as needed. To access the filter, remove the wing nut, washer, and cleaner cover.


The pump chamber should be filled before use to prevent overheating. Open the priming cap, located on the top of the pump housing, and pour in clean water. If the pump is started without being primed, shut it off immediately and let the pump cool completely before priming and restarting.

Starting the Engine:

1. The carburetor, located below the air cleaner, has two levers. Move the bottom lever to the right to turn the fuel valve on. Move the top lever left to close the choke.
2. Turn the engine switch to “ON.”
3. Move the throttle lever, located to the right of the carburetor, slightly to the left.
4. Pull the starter grip lightly until resistance is felt, then give it a hard pull. The engine should start.
5. As the engine warms up, gradually open the choke by moving the choke lever to the right. Once the engine is warm, adjust the throttle lever to the desired speed.

Stopping the Engine:

If the engine needs to be stopped immediately due to an emergency, turn the engine switch to “OFF.” Otherwise, do the following:

1. Move the throttle lever to the right.
2. Turn the engine switch to “OFF.”
3. Move the fuel valve left to “OFF.”

Where to Buy Parts for Your Honda Water Pump: is an OEM dealer offering parts for all of Honda’s power equipment from mowers to water pumps like the WD20. Whether you need an intake hose, a spark plug or a new pump housing, Honda Lawn Parts can help you find what you need. Their advanced search engine and online parts diagrams make it easy to identify the part you want, and it can be shipped to any address in the U.S. and Canada.

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