SMALL ENGINE TERMINOLOGY

Small engine terminology

Small engine terminology

Blog Article




Small engine terminology




Whether you’re a DIY enthusiast or just getting started with basic maintenance, it’s essential to understand key terms related to small engines. Many compact tools like lawnmowers, chainsaws, generators, leaf blowers etc., play a crucial role in our daily lives.



This comprehensive guide discusses small engine technology, breaking down complex jargon into easy-to-understand explanations. By the end of this post, you'll quickly understand different small engine terminologies to tackle projects and operate your devices.



Let’s get started.


1) Cylinder




Known as "Bore".There is an inner wall called a cylinder wall. It fits the piston accurately to the machined diameter. The inner wall is very smooth, allowing the piston and rings to work smoothly.


2) Cylinder block





    • An essential part of all small engines.






    • Inside the cylinder block are all the small engine parts.






    • It is made of aluminum.






    • Each specific engine must be cast in a mold to achieve its best appearance for proper operation.






    • Its exterior dissipates heat through aluminum alloy fins.






    • Some liquid-cooled engines may not have this type of fins on their cylinder blocks.






    • The single cylinder is the type found in most small engines. However, other parts of small engines have many cylinders; the most common are inline, opposed, and V configurations.






3) Blower housing





    • Sits around the flywheel.






    • It aims to direct air through the blower housing to cool the engine.






4) Flywheel





    • Sits above the engine.






    • It has a metal cover called the blower housing.






    • Works like a fan.






    • Cool the engine.







The blower housing protects the flywheel and other parts of small engines from exposure or human contact, which can cause injuries.


5) Cylinder head




Many small engines have a combustion chamber. A head gasket is attached to the top of the cylinder, called the cylinder head. The spark plug is housed in the cylinder head. There are three general types of cylinder heads:




    • A side-valve engine has both valves on one side of the engine.






    • The intake and exhaust valves sit on opposite sides of the cylinder.






    • The cylinder head holds both valves up.






6) Piston





    • It is made of cast steel or aluminum material.






    • The cylinder holds the piston.






    • The head is the piston top.






    • The piston mounts to the connecting rod via a pin and is fastened in place by retaining clips. A piston may have one to three rings. These top rings are used for compression. The bottom ring is known as the oil ring. Only four-stroke engines have oil rings. This ring cannot rotate because a pin inside the ring groove prevents any rotation.






7) Connecting rod




The connecting rod joins the crank to the piston. The wrist pin attaches the piston to the wrist pin and is secured by a clip. There may be one or two connecting rods. The bottom is removable on two-piece units.


8) Head gasket




Between the cylinder and the cylinder head is the head gasket. This gasket seals the cylinder. The function of the head gasket is to keep the pressure inside the combustion chamber. This component must withstand high temperatures. No water or coolant can enter the combustion chamber if the engine is liquid-cooled. A head gasket prevents this from happening.


9) Crankcase





    • The crankshaft is the part of the engine that rotates.






    • This part sits inside the crankcase.






    • The crankcase changes the up, down and circular motion of the piston.






    • It has heavy counterweights for balance.






    • It sits at a 90-degree angle on the cylinder.






    • There are three different types of horizontal engines: cars, some lawn tractors, and garden tillers.






    • Vertical types of engines include lawnmowers, outboard marine engines, and augers.






10) Bearings





    • Come in many styles and sizes.






    • They support engine parts.






    • They are resistant to corrosion and scoring.






    • They may or may not require lubrication.






    • They have small holes on the outside to lubricate the internal components.






11) Camshaft





    • Operates the intake and exhaust valves.






    • Two-stroke engines do not have a camshaft.






    • There is one lobe per valve.






    • The camshaft rotates, thereby lifting the valves.






    • Drive style of gears, chain or belt






    • Operates a push rod.






12) Valves





    • The valves are made of high-grade steel.






    • Valves are located on the cylinder block and the seal






    • The intake valve and exhaust valve create better airflow in the engine.






    • The intake valve is bigger than the exhaust valve.






13) Valve spring





    • Holds the valves closed, ensuring a tight seal maintains pressure on the camshaft.






    • It prevents the camshaft from floating.






14) Muffler





    • Reduces noise.






    • Made of metal






    • Bolted or threaded onto the engine






15) Starters (electric, rope rewind)





    • Crank the engine at high speed to start the system.






    • Draw fuel into the cylinder.






    • Create a spark from the ignition system






    • Found in products such as chainsaws, lawnmowers, and weed eaters.






    • Electric starter systems are found in cars, ATVs, marine engines and lawn tractors.






16) Carburetor




Mixes fuel with air for combustion.


17) Speed governor (air vane or mechanical)





    • Governors control engine speed.






    • Varies the throttle position to keep the engine at a specified RPM.






    • Increases engine speed.






    • It'll control the throttle so that the engine does not over-rev.






18) Transmission





    • Converts the output speed of the engine.






    • Used in machines such as lawn tractors, snow throwers, garden tillers






    • Creates a gear reduction to increase torque output.






19) Lubrication systems (splash lubrication, pressure lubrication)




The moving parts of the engine require constant lubrication.


20) Fuel line




The line through which fuel is transferred from the tank to the carburetor.


21) Throttle




Controls the amount of air-fuel mixture that enters the engine from the carburetor.


22) Battery




Stores electrical energy until it is needed to power devices.


23) Oil filter




Removes contaminants circulating in the oil.


24) Fans




Most small engines are air-cooled using fans located outside the combustion chamber.


Small engine safety tips





    • Always check the oil level before starting the small engine.






    • Add oil if necessary.






    • Always use the type of oil recommended by the operator’s manual.






    • Use the proper ratio if the small engine requires a mixture of oil and gasoline. Refer to the user’s manual for the correct mix.






    • Never fill the gasoline tank if the small engine is hot. Allow it to cool for several minutes before refueling. Please clean up any spilled gasoline before starting the small engine.






    • Don't smoke while filling the gas tank or operating the small engine.






    • Always store gasoline in an approved and properly labeled container. Use only approved gasoline for the small engine.






    • Never start the small engine in an enclosed area. Remember to start it in a well-ventilated area. Fumes or carbon monoxide can be dangerous in an enclosed room.






    • Never touch the small engine muffler when it is hot. The small engine muffler can become very hot. And it stays warm for a while after the small engine is turned off. If you accidentally touch it, you can get severely burned.






    • Never make any adjustments while the small engine is running.






    • Remember to disconnect the spark plug before performing maintenance and safety checks on machines with small engines.






    • Disconnect the spark plug when the machine is not in use. This safety mechanism will reduce the possibility of the machine starting by mistake.






    • Allow the small engine to cool before storing it in an enclosed space.






FAQs



1) What is the description of the small engine?




A small engine is a general term for a wide range of small displacement, low-power internal combustion engines used to power lawnmowers, concrete mixers, generators, and many other machines that require independent power sources.


2) What are the six systems of small engines?




Small gas engines consist of individual systems that work together to produce electricity. Every system has several components. Internal combustion gasoline-powered engines require six systems: exhaust, fuel, ignition, cooling, combustion, and lubrication.


3) How do you identify a small engine?




Model, type and code numbers, stamped directly into the small engine, are used to identify the small engines. Small engines used in lawnmower applications typically have the model numbers stamped directly on the blower housing, muffler heat shield, or a few inches above the spark plug.


4) How is engine size measured?




Engine size is the volume of air and fuel that can be pushed through the engine and is measured in cubic centimeters (cc). Car engine size is usually expressed in liters, rounded to the nearest tenth of a liter. For example, a car with a 1490 cc engine would be described as 1.5 liters.


5) What are some examples of small engines?




Small engines are essential to making our lives more efficient, from weeders and lawnmowers to snowblowers, pumps, chainsaws, generators and grain augers. All these machines require care and regular maintenance to ensure they run healthy for a long time.


Conclusion




Understanding the small engine terminologies is vital to anyone looking to maintain, repair, or understand the machinery that drives many of our outdoor devices. Whether you're improving efficiency or a homeowner looking to extend the life of your appliances, these insights will undoubtedly prove beneficial.



By staying informed and confident in the language of small engines, you'll keep your equipment in good working conditions.

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