What Are The Different Parts of a Lawn Tractor Engine?

Repower Pros provides high-quality OEM small engine parts for Pennsylvania homeowners to easily repair their lawn tractor engines. Some homeowners may be new to engine repair and don’t know the different parts of a lawn tractor engine. These engines generally operate with a 4-stroke, internal-combustion system. We can break down this system into three groups: the fuel/air system, the electric/ignition system, and the internal moving parts. Below, we’ll explain the parts of a lawn tractor engine to make repairing it easier. 

Fuel and Air Systems

Air Filter

The air filter is attached to the carburetor and filters dirty air entering the engine. It filters the air entering the combustion chamber, preventing dirt and debris from getting into the engine components. This helps reduce engine wear and improve efficiency. If your engine’s air filter is dirty, it won’t perform as well and will need to be replaced. 

Carburetor

The carburetor ignites and drives the engine piston by blending raw fuel and air together into a combustible mist that powers the engine. It ignites in the cylinder and supplies air and fuel to the combustion chamber. The engine’s throttle will control the amount of the air/fuel mixture that enters the engine from the carburetor.

Fuel Tank and Filter

The fuel tank stores the fuel for the lawn tractor. It supplies fuel through the carburetor to ensure the mower runs smoothly. Fuel lines take the fuel from the tank to the carburetor. In this system, there is also a fuel filter that traps impurities in the fuel before it can clog the carburetor. 

Electric and Ignition

Starter and Ignition Coil

The starter uses power from the battery to start the engine. The ignition coil produces high-voltage electricity that’s sent to the spark plug to ignite the fuel in the cylinder. An ignition coil is needed to fire the spark plug. It uses the flywheel as it rotates past it to produce electricity. If your engine is not working, the starter or the ignition coil is likely to be the issue. If the lawn mower won’t crank, the starter is the issue. If the mower cranks but doesn’t start, the ignition coil is the issue. 

Spark Plug

The spark plug creates a spark needed to power the engine. It delivers the electrical spark the engine needs to ignite the air/fuel mixture inside the engine’s cylinder. Spark plugs need to be checked regularly and will need to be replaced if they are worn and affecting engine performance. 

Flywheel

The flywheel is like the balancer for the engine, playing a significant role when the engine turns on. It’s made with heavy metal and operates as a wheel that spins with the engine to store rotational energy. It maintains engine momentum and uses magnets that pass by the ignition coil to trigger the electric spark. To cool the engine, the flywheel also has a fan. 

Internal Components 

All internal components of the engine are housed in the cylinder block.

Piston

The piston is a compression generator located in the crankcase. It moves up and down the cylinder, compressing the air/fuel mixture in an upward motion. Doing this converts compression pressure into mechanical force. Piston rings may also be on the piston, providing a seal between the piston and cylinder wall. The top rings are for compression, and the bottom rings are for oil. 

Connecting Rod

The connecting rod links the piston to the crankshaft. It transitions the piston’s linear motion into rotation to transmit force to the crankshaft. 

Crankshaft

The crankshaft is the main rotating shaft of the engine. It takes the up/down movements of the piston and turns them into rotational power for the flywheel. This turns the tractor’s PTO and drive wheels for easy use. If the crankshaft is bent, it will need to be replaced to properly move the piston. 

Valves

There are two different types of valves on an engine: intake and exhaust. They’re located on the cylinder block and seals. These valves open and close at certain times to allow the air/fuel mixture into the combustion chamber at the right time. The larger intake valve lets the mixture in, and the exhaust valve releases exhaust gases. With valves, you’ll have better engine airflow for your lawn tractor. Engines will also have mufflers to minimize the noise of the exhaust. 

Camshaft

The camshaft operates the intake and exhaust valves. It’s a rotating shaft with lobes that control the exact timing of when valves open and close. This is done by rotating to operate the push rod that will lift the valves. This component is crucial to maintaining proper airflow within the engine. 

Find Quality Engine Parts with Repower 

Repower Pros has all you need to get your engines into working condition again. Find a wide variety of aftermarket and OEM parts for engines for all major small engine brands like Kawasaki, John Deere, Briggs & Stratton, and more. For full engine rebuilds, we have engine rebuild kits that come with pictures and instructions to make it easy for homeowners to install. If you need quality parts for your small engines, contact us today.