How Much Do You Know About Small Engines?


By: Steven Symes

6 Min Quiz

Image: VisioRacer

About This Quiz

Can you tear into a lawnmower like a pro or do you need help like the average human does? What about really small car engines? Some of the same principles apply that you might know from big engines, but there are some unique issues surrounding small engines. 

Small engines are everywhere. They power our lawn mowers, leaf blowers, chainsaws, and countless other yard tools. Generators use them as well, so you can have electricity during a blackout, or far away from the power grid. Even some motorcycles, cars, ATVs, and other vehicles use small engines to move. What's truly interesting is that people who take really great care of their car will completely forget about these unsung heroes, until they don't work correctly. 

By knowing about small engines and how to maintain them, you can save a chunk of change on maintenance. After all, these need servicing frequently, so if you don't have to pay someone else to do it, that'll save you a ton of cash and downtime if you know how to fix them yourself. 

So, grab your socket wrench, gas can, and all your knowledge - you're going to need all three for this quiz. Take it now and see just how much you really know about small engines. 

What does a small engine carburetor mix?

Small engines have simple designs, like what you could find in larger engines long ago. This means that instead of electronic fuel injection, most feature a carburetor that is completely analog. You must adjust and clean it regularly for optimal performance.


Technically speaking, the majority of small engines use what to create power?

By burning fuel through small, controlled explosions, small engines produce power that can be used to spin a mower blade, generate electricity, spin a concrete mixer, or turn the wheels on a go-kart.


Before you clean a small engine carburetor, what must you do?

There are different carburetor cleaning products out there. Some people prefer the type you submerge the carburetor in, but others think the spray kind also works correctly. Whatever method you use, just remember to uninstall and completely disassemble the carb first, including removing all gaskets.


What additive in gasoline must you be careful with when it comes to small engines?

You must be careful about using gasoline with too much ethanol, since the additive can make starting and maintaining small engines difficult. That's because ethanol will attract water, which causes engine internals to corrode quickly. It also reduces the effectiveness of the combustion process, so the engine runs poorly.


What automaker is a big force in the small engine market?

Honda makes a number of legendary small engines, most notably the GC and GX lines. Like its cars, these engines have a highly respected reputation for reliability. That alone has made Honda a popular option for all kinds of small engine applications, like lawn mowers and generators.


What does the throttle on a small engine control?

Since most small engines use a carburetor, the air and fuel mix before entering the engine. The throttle is a simple device that controls how much of that mixture is allowed to flow into the engine at any given time.


What does a small engine spark arrestor help prevent?

Small engines have short exhaust systems, sometimes just a tiny port. That introduces a risk, because sparks can shoot out, possibly catching grass or other combustible materials on fire. While not perfect, a spark arrestor cuts down the chances of that happening.


What is the name of the component that controls when air-fuel flows into they cylinders and exhaust gases flow out?

In small engines, valves can either be positioned in an overhead arrangement or a side valve, depending on the design. The second of the two options is a simpler design, making it cheaper to produce and maintain, which is why it persists today.


What is the purpose of an engine primer?

When you use a primer on any small engine, it injects a little bit of fuel into the carburetor throat. That, in turn, results in a rich air-fuel mix, which will make starting an engine that is cold much easier.


If you pull a cord to start a small engine, what kind of ignition system does it have?

If your lawn mower, generator, etc. has a pull cord, that means it doesn't start using a battery, like your car. Pulling the cord turns a crankshaft, which powers the magneto to supply a spark for starting up the engine.


What part of a lawnmower engine spins the blade?

Engines used on lawnmowers have a vertical axis layout, that way the crankshaft attaches to the blade below. As the crankshaft spins, it spins the blade, making for a simple yet effective design.


What is the part of a small engine that lights the air-fuel mix in the cylinder?

Once the valve opens, letting the mixture of air and fuel into the cylinder and then closes, it's time to light the fuel, triggering combustion. That's done by the spark plug, which essentially is an insulated electrode. As high-voltage electricity passes through it, it travels over a small gap, igniting the fuel.


What is the name of the component that moves up and down inside a small engine's cylinders?

Even though it might seem like the pistons are being moved by the crankshaft, they are actually forced down by the forces created by combustion. That energy transfers to the crankshaft and is sent from there to whatever connects to the engine.


A Wankel small engine is also known as what?

Wankel or rotary engines aren't very common in vehicles, and the same holds true for small engines. Arctic Enterprise, for a time, offered a lawnmower with a Wankel engine back in the 1970s, but just like with cars, it lost out to more traditional designs.


The Tata Nano, which uses a notoriously small engine for a car, is sold in which country?

Known as the cheapest production car in the world, the Nano is made quite cheaply. The 624 cc two-cylinder engine does feature multi-port fuel injection, but it only produces 38 horsepower, which is weak even for such a small and lightweight car.


How does Caterham squeeze 80 horsepower out of the Seven's 660 cc engine?

While 80 horsepower from a 660 cc engine is impressive, that's not a ton of power. But, thanks to a super lightweight construction, the Caterham Seven can hit 100 mph and do 0 to 60 mph in 6.5 seconds, making for an entertaining car.


Can you buy the Fiat 500 Twin Air in North America?

With an 875 cc two-cylinder engine, the Fiat 500 Twin Air is unique even for Europe, which is the only market where you can buy this version of the car. Still, this small engine produces a surprisingly healthy 85 horsepower and 107 lb.-ft. of torque.


What was the smallest engine Ford offered for the Fiesta in the US, but then dropped it for 2018?

Thanks to slow sales, Ford decided to pull the 1.0-liter EcoBoost engine from the US market. Shoppers weren't impressed with the 123 horsepower and 148 lb.-ft. of torque, combined with 43 mph on the highway, despite this engine being hugely popular in other markets.


Why do small engines on seasonal machinery need to be serviced annually?

As your lawnmower, chainsaw, generator, or whatever sits in the tool shed or garage when you don't need them, all kinds of things can happen. One of the biggest problems is that water vapor condenses in the gas tank and engine, creating problems when you first fire up the engine. A full servicing is cheap and will ensure the engine keeps running smoothly.


Which of the following isn't a reason to service your small engine more often?

Small engines are a lot like other engines. If you use them harder or longer, you need to have them serviced more often, just like other mechanical devices. Staying on top of maintenance will help your engine last longer.


With small engines, what do you need to do when it's brand-new?

All small engine manufacturers have a recommended break-in procedure. If you don't know what it is, before you just start using the engine, you need to contact the manufacturer to get that information. Otherwise, you're risking serious damage.


Before installing a spark plug in your small engine, what should you do first?

Despite what some uninformed people think, spark plug manufacturers don't add a gap that will work for any engine. These spark plugs go in a whole range of engines, so use a gap tool to check that it matches what the engine manufacturer recommends.


When you're about to fire up a small engine after it's sat for several months, which of the following should you check?

Starting an engine that's low on oil can cause a serious problem. After all, oil keeps metal parts from grinding against each other, which will result in extensive damage to the engine. Taking a moment to check the oil level is just being smart.


What component keeps deposits from the gas tank from reaching the carburetor or combustion chamber?

Deposits, including any corroded metal that comes off the inside of the gas tank, will cause serious clogs in the fuel line, or create deposit buildups in the combustion chamber. Either way, your engine will run roughly or not as efficiently. Replace the fuel filter once a year so the fuel flows normally.


What can you add to the fuel tank before putting a small engine in storage?

Many people don't realize that fuel sitting in the tank for months on end will start to change chemically. By adding fuel stabilizer, you avoid problems with starting the engine and having it run smoothly once you take the engine out of storage.


Which of the following isn't a benefit of properly maintaining a small engine?

Many people don't give a second thought to maintaining the engine for their mower, leaf blower, generator, etc. even though they meticulously care for their car. You'll experience fewer problems and spend less on gas if you do, so it's worth the effort.


What can you use to remove the spark plug from a small engine?

You'll need to swap the spark plug in most small engines once a year, so knowing how to do this can save you the fee you'd pay a shop. A spark plug attachment grabs the plug, but won't damage it, so you can properly tighten or loosen it.


How often should you check the oil level on a small engine?

Unlike your car, a small engine needs to have the oil checked constantly. It's an easier procedure, but you should always have extra oil on hand so you can top it off if the level is too low before you fire up the engine.


How long should you store gas for your small engine?

Believe it or not, gas that sits too long starts to degrade. This is especially true if ethanol is added to the fuel. While you can use a stabilizer, it's simpler and cheaper to not buy and store too much. Instead, get more at the fuel station as you need it.


When changing the oil, what else do you need to swap out?

Just like with a car's engine, you must replace the oil filter when you swap the oil. The filter gets full of the stuff picked up by the oil, so it needs to be changed regularly. A fresh filter will keep the oil clean longer, which has several benefits.


What's the fewest number of cylinders a small engine can have?

It might seem ridiculous, but small engines often have only one cylinder. This includes engines that power many lawnmowers, chainsaws, leaf blowers, etc. If a lawnmower is a type you can ride on, it likely has two cylinders.


What's one reason why many small engines are so noisy?

If you haven't noticed, old cars that are air-cooled also run louder than modern vehicles. Also, small engines usually don't have an exhaust system with a muffler, which helps keep the noise level down.


What keeps the cylinder head attached to the engine block in a small engine?

Because you might need to remove the cylinder head later, manufacturers use bolts to keep it attached to the engine block. Of course, if you remove it, you must tighten the bolts to the torque specs from the manufacturer.


What does it mean if your small engine starts putting out blue or white smoke?

If you see this problem with your small engine, check that there isn't too much oil. Another possible reason could be that you're using the wrong oil weight. If the smoke you see is black, the cause is likely a fuel or air clog that's throwing off the air-fuel mixture.


Which of the following is a possible cause of a small engine making a knocking sound?

When this happens, it's time to open up the engine and check out the piston. Use a wire brush to remove deposits. Another possible source is the flywheel and key, which sometimes come loose and cause a knocking sound.


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