Tag Archives: GXH50 Honda Engine

Horizontal vs. Vertical Engines

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Horizontal vs. Vertical Engines

Drive shaft orientation is one of the most misunderstood aspects of small engines, leading to a lot of fallacies about the advantages and disadvantages of each design. How do you know which one you own? Does one design last more than the other? Is there a reason you should choose a vertical shaft engine over a horizontal shaft or vice versa? Here’s what you need to know to separate fact from fiction.

Model Designations

All Honda engine model names start with two letters to designate their engine family. Currently, this includes the GX and GC. If there’s a “V” after these two letters, the engine has a vertical shaft. Engines that are the same model family and displacement share the same basic design and provide identical performance no matter how the shaft is oriented.

Engine Wear and Lubrication

Myths are persistent about one design wearing out faster than the other, but these can be attributed to a misunderstanding about how these engines work.

Some older vertical shaft engines have the intake and exhaust valves positioned vertically. This draws hot exhaust gases along the bottom cylinder surface, resulting in slightly more wear on that side.
This has led people into believing that gravity is a factor, leading to increased wear on vertical shaft engines, but the same wear pattern is found around the exhaust no matter where the valve is positioned.

On the other hand, some people believe that horizontal shaft engines will wear out faster because the upright position of the cylinders keeps them from being lubricated as well as a vertical shaft engine. Both horizontal and vertical engines with splash lubrication use a dipper or scoop to pick up oil in the crankcase and fling it onto the components inside the engine. Even at idle, oil is being flung around the engine at a rate of 20-30 times per second, overcoming any issues with gravity by sheer force. Likewise, while the oil channel location may be a little different, pressurized oiling systems still pump oil up to the head and let it flow back to the crankcase in both engine designs.

Driving Equipment

When engineers choose an engine, they decide on crankshaft orientation based on what makes the most sense to power the equipment. For example, the blade can be bolted directly to the drive shaft on a vertical shaft engine when used in a walk-behind mower, while a horizontal shaft is perfect for the pulley system used on an edger or the impeller in a water pump.

The only time you’ll likely have a choice between vertical and horizontal shaft engines is when you buy a riding mower. Some ZTR manufacturers choose to use horizontal shaft engines to reduce the overall length of the mower, while some older lawn tractors including several of Honda’s own models use a horizontal shaft engine to connect with the axle using a shaft drive. To connect the horizontal shaft to a vertically-oriented pulley, these mowers use a mule drive. This guides the belt along a pair of pulleys, bending them at a 90-degree angle. These added bends are more efficient and reliable than they sound, but they do complicate belt replacement.

Blurring the Line: Mini 4 Stroke Engines

The GX25 and GX35 are technically vertical shaft engines, but their oiling system is designed to work at any angle. This lets them be used in place of two-stroke engines in handheld devices like string trimmers. These engines also find use in stationary equipment, mounted either horizontally, as seen in Honda’s own WX10 water pump, or vertically to power small augers.

Get Everything You Need for Your Honda Engine

No matter how your engine is built or what it’s powering, you can get the parts you need for it from www.hondalawnparts.com. We’re a certified dealer for Honda Engines and Honda Power Equipment so we can ship the OEM parts and accessories across the U.S. and Canada. Need help finding a part? Our site can show you factory parts diagrams and descriptions for your specific model so you know what you’re ordering will fit.

GXH50: The Engine of Choice for Work and Fun

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GXH50: The Engine of Choice for Work and Fun

Honda’s GHX50 is easy to overlook, but this tiny engine has managed to make its way into products ranging from home generator to mining equipment, and it’s even found a niche in motorsports. What is it that makes this 50 cc engine popular with hobbyists and professionals?

Small Scale Power with Full Scale Features

Although Honda sells it as part of their mini four-stroke series, this engine doesn’t have the oil baffle system that lets engines like the GX25 and GX35 operate at any angle. Instead, it’s intended for use in applications where it will be kept upright. As the “GX” name implies, this is a professional quality engine, sharing many design features with larger models in the lineup.

This starts with an overhead valve design with an 8.0:1 compression ratio. This helps the engine generate 2.1 hp at 7,000 RPM and, 2 lb-ft. torque at 4,500 RPM, while a wide torque curve lets it run effectively at lower speeds to conserve fuel and keep it from bogging down during heavy loads. The onboard 0.8-gallon tank can keep the engine running for about 4 hours.

An automatic mechanical decompression system relieves cylinder pressure when turning over the engine. Combined with the low weight of the piston and valvetrain, the engine is extremely easy to start. It also uses a float carburetor instead of the more finicky diaphragm carburetors usually found in engines of this displacement.

Like larger engines, the GHX50 comes with a carburetor drain plug and an oil drain plug so the engine doesn’t need to be tilted to drain old oil and fuel. An automotive-style paper filter protects the engine from fine debris, while an optional spark arrester makes the GHX50 legal for use in areas prone to fire. Most servicing is done at 50 hr/6 months and 100 hr/1 year intervals.

The piston is connected to a forged steel crankshaft supported by ball bearings to ensure years of trouble-free use, while the Oil Alert system shuts down the ignition if the oil level is too low, protecting the engine from premature damage. Like Honda’s other engines, this motor is both CARB and EPA certified, making it legal to buy and operate across the U.S. and Canada.

The entire engine including the muffler and fuel tank measures just 8.9 x 10.8 x 13 inches and weighs just over 12 lbs. without fluids. This makes it a great choice for applications where weight and size are at a premium.

Industrial and Residential Applications

If a piece of power equipment needs to be carried by hand, there’s a good chance someone has made a version powered by this engine. While used in a variety of equipment, its most popular application by far is in water pumps, whether they’re built for draining mine shafts, irrigating farmland or fighting fires. Honda uses the engine into its own WX15 lightweight water pump and EU1000i inverter generator.

Motorsport

The GHX50 may seem out of place next to superbikes and race-prepped NSX’s, but the company considers it to be one of its most important offerings. Most racers start their climb through racing series at a young age with go-karts, including most of the current F1 drivers. Even three-time world champion Ayrton Senna started his career behind the wheel of one of these karts.

Seeing dwindling interest in Junior Karting due to high engine costs, Honda Performance Development created a kit to adapt the GHX50 to kart use. The engine’s industrial roots make running costs extremely low: despite being constantly pushed to its limit, it can last well over 200 hours between rebuilds. This gives young racers a chance to get the thrill of racing with a safe level of power that lets them hone their skills.

This has also drawn attention from other hobbyists, adapting the engine to motorized bicycles and minibikes. It’s small enough to fall within displacement restrictions in most areas for road use, and since it’s completely self-contained, there’s no need to worry about routing a muffler or fitting a fuel tank. Best of all, it’s far more reliable than the two strokes usually used in these applications.

Getting Parts for the GHX50

No matter what your Honda engine is powering, you can get quality OEM parts for it from www.hondalawnparts.com. We’re a certified dealer for Honda Engines and Honda Power Equipment, letting us ship parts for their products across the U.S. and Canada. Not sure what part you need? Our site has built-in factory diagrams so you can see exactly what you’re ordering and where it fits on your engine.