Honda GS 190 Maintenance Guide

GS190.3The GS 190 may be small, but with features like a cast iron cylinder liner, it can deliver the reliability you expect from a commercial-grade engine. Whether your GS is powering a tiller, pressure washer, water pump, or a piece of farm equipment, this guide will help you keep your engine running reliably.

Maintenance Schedule

Honda recommends performing the following services:

  • Before each use – Check air filter and oil level.
  • First month or 5 hours of operation – Change the oil.
  • Every three months or 25 hours – Clean the air filter.
  • Every 6 months or 50 hours – Change the oil.
  • Every year or 100 hours – Check the spark plug and (if equipped) the spark arrester.
  • Every two years or 200 hours: Replace the air filter and spark plug.

Honda recommends taking the engine into a dealer for the following maintenance service:

  • Every 6 months or 50 hours – Check the idle speed and valve clearance and clean the fuel tank and filter.
  • Every two years – Inspect the fuel lines.


This engine should be used with fresh unleaded gas with an octane rating of at least 86 and no more than 10% ethanol (E10) or 5% methanol. When filling the tank, never go past the base of the filler neck, and make sure the cap makes an audible click when closing. Move the engine at least 10 feet (three meters) away before starting to prevent ignition of any remaining fuel vapor.


Honda recommends 10W30 motor oil that meets API service category SJ or later, but SAE 30 can also be used at temperatures above 50 degrees F (10 degrees C.) The crankcase holds 20 oz. (0.58 l) of oil.

To check the oil, unscrew the dipstick from the filler neck, wipe it clean, and reinsert it into the engine without screwing it back in. Add oil if there’s nothing above the bottom mark on the dipstick. Some models come with the Oil Alert system. If the engine stops suddenly, check the oil level to make sure this didn’t trigger the system and shut down the motor to prevent internal damage.

To change the oil, place a container to catch the used oil below the engine for recycling. Remove the oil filler cap/dipstick, followed by the drain plug and washer below and to the left of the filler neck. Once the oil has drained, screw the drain plug and washer back in, add the new oil through the filler neck, and screw the dipstick back in.

Air Cleaner

To access the air cleaner, press in the tabs on the cover, opposite of the engine. The cover should flip up, giving you access to the filter elements. There are three parts to the filter: a paper filter element, a mesh grid, and a foam filter element.

To clean the paper element and grid, simply tap them against a hard surface.

To clean the foam element, wash it in soap and water and let it dry. Soak the element in clean engine oil and squeeze out any excess.

Before reinstalling the filter, wipe away any dirt on the inside of the air cleaner body.

Spark Plug

To remove the spark plug, disconnect the plug cap and clean out any dirt surrounding the plug. Unscrew the plug using a spark plug wrench.

The spark plug gap should be between 0.028-0.031 inches (0.70-0.80 mm.) Replace the spark plug if the electrodes are worn or the spark plug is otherwise damaged.

To install the spark plug, tighten it by hand to prevent cross-threading, then tighten with the spark plug wrench, turning 1/8-1/4 turn after seating if the plug is used, or 1/2 turn if the plug is new. Reattach the cap.

Spark Arrester

The spark arrester is optional equipment, but it can be added to any GS 190 to comply with local safety laws.

To access the arrester, remove the three 6mm bolts from the muffler protector. The protector should slide off. Next, remove the single 4mm bolt holding the arrester inside the muffler. Slide out the arrester.

To clean the arrester, remove any carbon build up with a wire brush. Replace the arrester if it’s cracked or has any large holes.

Where to Get Parts for Your Honda GS 190 is a certified Honda small engine equipment dealer, carrying everything you need for your GS-series motor, no matter what it’s powering. Our site has built-in factory parts diagrams and descriptions, making it easy to find exactly what you’re looking for. We can ship parts and accessories anywhere in the U.S. and Canada.

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