Maintenance Guide for a Honda WH15X

Honda WH15XLike any piece of small engine equipment, Honda’s WH15X water pump requires regular maintenance to provide optimum performance. This guide will help you keep your pump in tip top shape.

Stay Safe!

The WH15X is capable of moving large amounts of water long distances. That same power can mean serious injury if handled improperly. When working on the pump, don’t run the engine until the repair is complete or the instructions tell you to start the motor, and don’t run the motor in any place where carbon monoxide fumes could accumulate, such as next to or inside a building. Be aware that the exhaust can stay hot enough to cause burns several minutes after the engine has been shut off. Above all, keep ignition sources including cigarettes, sparks and fire away from fuel system parts.

Maintenance Schedule

1. Before each use: Check the oil level in the engine and the condition of the air filter.

2. Every three months or 50 hours: Clean the air filter.

3. Every 6 months or 100 hours: Change the oil and check the spark plug. Clean the sediment cup, fuel tank and filter. Honda recommends having the fuel system serviced by a professional.

4. Every year or 300 hours: Replace the spark plug and have the pump serviced by a dealer or professional mechanic. They will need to check the idle speed, valve clearance and impeller.


The engine in the WH15X is designed to work with unleaded fuel that is 86 Octane or greater containing up to 10% ethanol (E10) or 5% methanol. The fuel level should not go past the top of the screen inside the tank opening. Always use fresh fuel to ensure proper combustion.

Checking, Adding and Changing Oil

The oil fill cap on the engine has a dipstick attached to it. To check the oil level, remove the cap, wipe off any oil, and slide it back into the engine without screwing it back in. Remove the cap and look at the markings on the dipstick.

The drain plug is located at the base of the engine, just to the left of the fill cap. The oil will drain faster if the engine is warm. When adding oil, the level should come up to the edge of the cap opening.

The engine holds 0.63 quarts (0.6 liters) of oil. Honda recommends 10W-30 for temperatures between 23°F and 104°F (-5°C and 40°C,) while SAE 30 can be used in temperatures between 50°F and 104°F (10°C and 40°C.)

Air Filter

The filter assembly is made up of 5 parts with a grid at the bottom followed by the filter, air cleaner cover, cover washer and wing nut. Unscrewing the wing nut allows the complete assembly to be removed from the engine and disassembled for inspection and cleaning.

To clean the filter, wash it using a nonflammable solvent or mild soap and water. Once the filter is dry, soak it in clean engine oil and squeeze out any excess. Wipe away any dirt that has collected on the other parts of the assembly. The engine may smoke when first stared if there is too much oil in the filter.

Sediment Cup

Turn the fuel valve to the “Off” position. Unscrew the sediment cup and remove the O-ring from the fuel valve. Wash both parts using a non-flammable solvent. Once both parts are completely dry, put the O-ring back on the valve and re-install the cup. Switch the fuel valve to “On” and check for fuel leaks.

Spark Plug

The plug can be removed by taking off the spark plug cap and unscrewing the plug with a 13/16 plug wrench.

The gap between the electrodes should be between 0.028 and 0.031 inches (0.70 and 0.80 mm.) Replace the plug if there is damage or excessive wear to the electrodes or insulator. Honda recommends using an NGK BPR6ES or Denso W20EPR-U spark plug.

Spark Arrester

To access the arrester, unbolt the muffler assembly from the engine. Remove the four screws holding the protector to the muffler. Remove the single screw holding the arrestor inside the muffler and slide it out. Follow these steps in reverse to reinstall the muffler, making sure the seal is still on the opening to the engine.

The arrestor can be cleaned with a wire brush. If the arrestor shows any signs of damage, it should be replaced. This is an optional piece of equipment, but it can be added to the muffler of any WH15X as needed to meed local safety requirements.

Where to buy Honda Water Pump parts

Whatever part you may need for your Honda pump, has it. Finding what you need is easy: talk to their experienced staff or find it yourself by accessing their extensive parts diagrams database.

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