Things You'll Need
Engine oil container
Quart of SAE 10W-30 engine oil
The Honda GCV135 is a vertical-shaft residential-grade small engine, featuring an overhead valve design, 135 cc of displacement and a maximum brake horsepower rating of 4.3 at 3,600 revolutions-per-minute. According to Honda, oil changes should be conducted every six months or 50 hours under normal operating conditions; heavy use may require oil changes every 25 hours. Honda recommends changing the oil after the first five hours of use, or when the engine reaches the first month mark of operation.
Move the lawnmower to a flat level surface.
Turn the fuel valve lever clockwise to shut-off the fuel supply to the carburetor. The fuel valve lever is located to the right of the air cleaner, below the fuel tank.
Examine the exhaust-side of the engine and locate the oil filler cap, positioned below the pull cord handle, near the bottom of the crankcase. Unscrew the oil filler cap.
Wipe the threaded portion of the oil filler cap and attached dipstick with a disposable rag. Place the oil filler cap to the side, away from dirt or debris.
Place the oil container next to the engine's oil fill hole. Tilt the engine toward the oil container and allow the oil to drain from the crankcase. Restore the lawnmower back to the normal position.
Clean any residual oil from the engine's crankcase and mower deck, using a disposable rag. Seal the oil container to avoid accidental spillage.
Insert the small end of the funnel into the engine's oil fill opening. Pour approximately half of the one quart container of oil, in a slow manner, into the wide opening of the funnel. Be sure to hold the funnel with one hand when filling the crankcase with oil.
Replace the oil filler cap; remove the oil filler cap and check the dipstick. Fill the engine with a gradual amount of oil until the oil level reaches the upper horizontal mark on the dipstick. Wipe off the dipstick after each oil level check.
Replace the oil fill cap after reaching the appropriate oil level.
Turn the fuel valve lever counterclockwise to restore the fuel supply to the carburetor.
Dispose of the spent oil and soiled rags according to your local environmental disposal laws.