Servicing the Honda GX Series

Servicing the Honda GX Series

From pressure washer to debris loaders, if Billy Goat makes it, they offer it with a Honda GX-Series engine. Here’s what you need to know to ensure this engine delivers reliable service.

Maintenance Schedule

Before each use: Check the engine oil level and air filter.

First month or 20 hours: Change the engine oil

Every three months or 50 hours: Clean the air filter

Every 6 months or 100 hours: Change the oil, clean the sediment cup, check the spark plug and clean the spark plug arrester.

Every year or 300 hours: Replace the paper air filter and spark plug.

Every two years: Check the fuel tube.

On models with a reduction gear, the gear oil level should be checked before each use and replaced at the same time as the engine oil.

Honda recommends bringing the engine in for service every 6 months or 100 hours to clean the fuel tank and filter, and every year or 300 hours to check the idle speed and valve clearance.


This engine is designed to run on unleaded with an octane rating of 86 or higher and up to 10% ethanol, 5% methanol or 15% MTBE. Fuel should be used within one month of purchase or three months if treated with a stabilizer. The tank should never be filled past the top of the strainer in the filler neck. If your engine’s tank doesn’t have this filter, only fill the tank within one inch of the top.

Light pinging is normal under heavy loads, but if it’s persistent, consider switching to a different gasoline.


To check the oil, remove the oil filler cap and wipe off the dipstick. Insert the dipstick without screwing it back into the filler neck.

To change the oil, remove the bolt at the base of the engine just to the left of the filler neck and let the used oil flow collect into a container for recycling. Add new oil until it reaches the top of the neck.

Billy Goat aerators have a reduction gear built into the side of the engine. The oil should reach the top of the oil check bolt on the side of the case. To change the oil, let the engine warm up. Shut off the engine, remove the check bolt, and tilt the engine forward to drain out the old oil. Add fresh oil through the filler bolt hole in the top of the case until it reaches the check bolt hole.

Honda recommends using 10W30 in the engine and gear case for most operating conditions.

Air Filter

To access the filter elements, remove the wing nut on the top of the air cleaner cover, followed by the cover and a second wing nut.

To clean the outer foam element, wash it in water and a mild detergent, or soak it in a non-flammable solvent. Once dry, soak the foam in clean engine oil and squeeze out any excess.

To clean the foam element, knock it against a hard surface to remove any loose dirt.

Before reassembly, wipe out any dust that has gathered on the base or cover of the air cleaner. Make sure there is a gasket fitted to the base of the cleaner where the air enters the carburetor.

Spark Plug

To access the spark plug, disconnect the plug cap and unscrew the plug with a 13/16 inch plug wrench.

The spark plug gap should be between 0.028 and 0.031 inches (0.70-0.80 mm.) Replace the plug is the electrode is worn or the plug is damaged or fouled.

Thread the plug in by hand to avoid cross-threading, then tighten with the plug wrench. Once the plug seats, turn another 1/8-1/4 turn if it was used, or ½ turn if the plug is new. Reinstall the spark plug cap.

Sediment Cup

This cup is located directly below the fuel valve and to the right of the carburetor drain bolt. To remove, turn the fuel valve off, then unscrew the cup. Pour out the gas and debris into a suitable container and remove any remaining residue with a non-flammable solvent. When reinstalling, make sure the o-ring is fitted to the lip of the cup.

Spark Arrester

A spark arrester may be required in some locations to meet local fire safety regulations and can be added to any engine.

Remove the four screws holding the protector onto the muffler, along with two screws holding the exhaust deflector onto the muffler. Remove these pieces and slide the arrester out of the muffler opening.

Clean off any deposits with a wire brush. If there are holes or cracks in the spark arrester, it should be replaced.

Getting Parts for Your Billy Goat’s Engine is a certified dealer for Billy Goat and Honda Engines so you can get everything you need for your Billy Goat equipment from one source. We can ship anything you need to any address in the United States or Canada.

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