Honda GX120 1990 Owner's Manual

Honda GX120 1990 Engine manual cover
Pages 39
Year 1990
Language(s)
English en

Honda GX120 1990 Engine Specification

The Honda GX120 1990 engine is a robust and reliable power unit designed for a variety of industrial and commercial applications. It features a four-stroke, single-cylinder overhead valve (OHV) design, which enhances efficiency and performance while ensuring durability. With a displacement of 118 cubic centimeters, the engine delivers a maximum output of approximately 3.5 horsepower at 3,600 revolutions per minute. The bore and stroke measure 60 mm and 42 mm respectively, optimizing the engine's power-to-weight ratio.

The GX120 is air-cooled, which simplifies maintenance and reduces the risk of overheating during prolonged use. Its compression ratio is set at 8.5:1, contributing to its fuel efficiency and consistent power delivery. The engine incorporates a transistorized magneto ignition system, providing reliable starting and smooth operation. A centrifugal governor maintains engine speed under varying load conditions, enhancing stability and performance.

Fuel is supplied via a horizontal carburetor, designed to offer precise air-fuel mixture control for optimal combustion. The GX120 uses unleaded gasoline, and its fuel tank has a capacity of approximately 2 liters, allowing for extended operation without frequent refueling. The engine's lubrication system is a splash type, ensuring adequate oil distribution across moving components to minimize wear and extend engine life.

The GX120's compact design, with dimensions of about 305 mm in length, 362 mm in width, and 335 mm in height, allows for easy integration into a variety of equipment. Weighing approximately 12.1 kg, it is lightweight yet sturdy, providing a versatile power solution. The engine is equipped with a recoil starter, making it easy to operate even in remote locations. Overall, the Honda GX120 1990 engine is a blend of efficiency, reliability, and performance, suited for demanding applications.

Honda GX120 1990 Engine F.A.Q.

How do I change the oil in a Honda GX120 1990 engine?

To change the oil in a Honda GX120 engine, first ensure the engine is off and cool. Remove the oil filler cap, place a suitable container beneath the oil drain plug, and remove the plug to drain the oil. Once drained, replace the drain plug, and refill with the recommended oil up to the appropriate level.

What is the recommended spark plug for a Honda GX120 1990 engine?

The recommended spark plug for the Honda GX120 engine is the NGK BPR6ES or an equivalent. Ensure the gap is set to 0.7-0.8 mm for optimal performance.

How can I troubleshoot starting issues in my Honda GX120 engine?

If your Honda GX120 engine won't start, check the fuel level and quality, inspect the spark plug for wear or fouling, and ensure the air filter is clean. Also, verify that the choke is engaged if the engine is cold.

What maintenance schedule should I follow for my Honda GX120 engine?

Regular maintenance for the Honda GX120 includes checking the oil level before each use, changing the oil every 50 hours of operation, cleaning the air filter every 25 hours, and replacing the spark plug every 100 hours.

Why is my Honda GX120 engine overheating?

Overheating can be caused by a dirty air filter, low oil level, or poor ventilation around the engine. Ensure all cooling fins are clean and unobstructed, and replace any damaged parts.

How do I clean the carburetor on a Honda GX120 engine?

To clean the carburetor, first remove it from the engine. Disassemble the carburetor, carefully clean all components with carb cleaner, and ensure all passages are clear. Reassemble and reinstall the carburetor.

What type of oil should I use for a Honda GX120 engine?

Use SAE 10W-30 motor oil for general use in a Honda GX120 engine. For temperatures below 10°C, SAE 5W-30 is recommended. Always check the manufacturer’s guidelines for oil specifications.

How do I adjust the governor on a Honda GX120 engine?

To adjust the governor, loosen the governor arm bolt, push the governor arm to open the throttle fully, and rotate the governor shaft in the same direction. Tighten the bolt and ensure the throttle operates smoothly.

Why is my Honda GX120 engine running rough?

Rough running can be due to a dirty air filter, clogged fuel line, or a faulty spark plug. Inspect and clean these components, and replace any that are damaged or excessively worn.

How do I store my Honda GX120 engine for long periods?

For long-term storage, drain the fuel tank and carburetor, change the oil, remove the spark plug and add a few drops of oil into the cylinder, and pull the starter cord slowly to distribute the oil. Store the engine in a dry, clean place.