Parts for Briggs & Stratton 12S500 (0005-3856): Muffler / Base-Air Cleaner Parts

Seals between crankcase and crankshaft to prevent oil leaks and contamination. Replace if you notice oil pooling or engine performance issues.

This part is a breather gasket. This specific breather gasket is manufactured for use with small engines. The breather gasket forms a seal between the breather and the cylinder. The breather itself relieves the pressure that is inside of the crankcase by allowing the air to exit but not allowing the air to enter. A new breather gasket may be needed if the breather itself seems to be clogged. It can sometimes become clogged with oil. It's recommended to replace the breather gasket any time the breather itself is serviced to ensure that a proper seal is maintained. This part is a genuine Midwest Engine part and is an OEM part sourced directly from the manufacturer and it is sold individually. This specific breather gasket is compatible with engines, lawnmowers, and generators that are manufactured by Midwest Engine, Briggs and Stratton, Toro, and Lawn Boy.

Crankcase gasket creates an airtight seal to prevent oil and air leaks. Replace when deteriorated from heat and pressure. Confirm fit with model number.

Lower oil seal prevents engine oil leaks in small lawn and garden engines. Replace if you notice oil pooling or reduced performance. Verify fit with your engine model number.

Replace your engine flywheel if your lawn mower won't start or has weak spark. This part stores rotational energy and triggers the ignition system.

Engine won't restart after hitting an object? A sheared flywheel key is often the cause. This small part keeps the flywheel connected to the crankshaft.

Piston ring set for small engines. Installs around the piston to maintain compression. Replace if rings are worn, cracked, or broken for proper seal.

Fix engine knocking or power loss with this piston pin lock. Secures the piston pin in small engines. Basic mechanical skills needed for installation.

Outer trim panel for lawn and garden engine control area. Replaces cracked, dented, scratched, or warped facia. Restores finished appearance.

This screw is a genuine Midwest Engine replacement part for small engine appliances, including lawn tractors, lawn mowers, snowblowers, leaf blowers, vacuums, and tillers. The purpose of a screw is to tightly link materials together through rotation that pierces into the material. A screw might have to be replaced in the event that it is lost or misplaced, a common occurrence due to its size. A screw might also be replaced if it deteriorates over time, through erosion, cracking, or piercing, thereby reducing its efficacy in holding materials together. This kind of damage can be attributed to general overuse, to age, or simply to long-term exposure. If a screw is subject to any of this kind of damage, it is best to replace it immediately, as the materials held together by the screw must continue to be held together. Remember to always wear gloves when handling, repairing, and operating outdoor equipment. This screw is compatible with the following brands: Briggs & Stratton, Toro, Cub Cadet, and Lawn Boy.

Engine running rough or losing power? A worn exhaust valve may be the culprit. This valve controls exhaust gas flow for proper engine performance.

Replace a worn valve retainer if your engine has compression loss or valve train noise. This washer-shaped part secures the valve spring lock on the valve.

This is a genuine intake gasket replacement that is designed for use in certain lawn mower engines. This specialty intake gasket is what is responsible for creating the seal between the carburetor and the breather tube so that no gases or fluids leak when they pass between the two. This gasket is subjected to constant high pressure, vibrations, and extreme temperatures, and over time it will need replaced. Gaskets are generally considered a part of routine maintenance on most engines, and many owners will choose to keep a few extra on hand in case of an urgent repair need. This genuine OEM intake gasket is manufactured by Briggs & Stratton and designed to offer an identical replacement for the original gasket that came on the new unit. It is compatible with lawn mower engines in models from Briggs & Stratton and Toro, and will fit on over 150 different engine models in lawn mowers from these brands. The intake gasket is made of durable composite material. It is also a good idea to replace gaskets when servicing the carburetor to ensure a proper seal after reassembly. Be sure to use the right tools to install this part so that it isn't damaged in the process.

Replace a frayed or broken starter rope that prevents your lawn mower engine from starting. Simple DIY repair that restores pull-start function.

Can't start your engine? A frayed or broken starter rope grip prevents pull-starting. This replacement rope grip restores easy starting in 15 minutes.

Replacement mounting screw for lawn and garden engines. Secures components together during operation. Replace if stripped, missing, or damaged.

Flange screw for lawn and garden engines. Distributes connection force over a larger area. Replace if threads are stripped, head is damaged, or screw is missing.

Mounting screw for lawn and garden engines. Secures engine components and covers. Replace if stripped, corroded, missing, or damaged during maintenance.

Complete carburetor overhaul kit for small engines. Includes gaskets, diaphragms, and seals to restore proper fuel-air mixing. Replace when engine runs rough or won't start. Verify fit with your model number.

Fix a flooded carburetor with this float. Controls fuel flow to the carburetor bowl, preventing flooding and ensuring proper air-fuel mixture.

Seals between carburetor and air filter on lawn and garden engines. Replace if worn, cracked, or leaking to prevent dirty air from affecting performance.

Mower won't start or runs poorly? Cracked or leaking fuel lines prevent proper fuel delivery. Simple 15-minute DIY repair restores engine performance.

This governor spring is a genuine Midwest Engine part, sold individually. This governor spring can be used as a replacement part for a pressure washer. The purpose of a governor spring in a pressure washer is to open the throttle of the appliance and maintains its positioning so that the speed and pacing of the appliance can be controlled by the operator.The governor spring might have to be replaced if it suffers damage that affects its ability to maintain spring tension. The governor spring could be cracked, punctured, scraped, or eroded from general wear and tear over long-term use or as the result of an accident that warps the component beyond functionality. If this occurs, the governor spring should be removed and replaced by this genuine OEM replacement part. Remember to always wear gloves when handling, repairing, and operating outdoor equipment. Always unplug the appliance before performing any kind of repair or replacement.This is an OEM part sourced directly from the manufacturer, and it is sold individually. This governor spring is compatible with the following outdoor appliance brands: Midwest Engine and Briggs & Stratton.

The choke return spring is a part that is used on many small engines in lawn and garden equipment. The part is a component in the choke system that ensures that the correct tension is applied to keep the choke lever in the appropriate position. If the choke return spring is broken or begins to malfunction, the lawnmower may have issues keeping power and running correctly.If the choke return spring is damaged or weak, it will prevent the choke from returning to the correct position. This can cause the engine to speed up and accelerate more quickly than desired. The air filter housing will need to be unscrewed to access the choke return spring. Take the wire off the spark plug and remove the boot from the plug. Remove the spring from the linkage and then clip on the new one. Replace the other components to get the equipment to work again.This choke return spring is an authentic OEM replacement part directly sourced from the manufacturer. It is sold individually. The spring is compatible with various wood chippers, lawnmowers, and pressure washers by Briggs and Stratton, Simplicity, Toro, Lawn-Boy, and Cub Cadet.

In-line fuel filter prevents contaminants from entering your engine's carburetor. Replace if clogged to restore fuel flow and prevent starting issues.

Control wire casing for lawn and garden engines. Protects and guides throttle or choke control cables. Replace if cracked, split, or missing.

Control wire for lawn and garden engines. Connects controls to engine throttle or choke mechanisms. Replace if frayed, broken, kinked, or missing.

Sealing washer creates a leak-proof seal in your lawn and garden engine. Replace when worn or cracked to prevent oil or fuel leaks. Confirm fit.

Metal rear door panel for dryer drum access. Replaces cracked, dented, or rusted panels. Mounts to back of dryer cabinet for maintenance access.

Metal mounting screw for lawn and garden engines. Secures components together throughout the equipment. Replace when stripped, rusted, or missing.

Spark plugs work by providing an electric spark in a combustion chamber, igniting the mix of fuel and air that allows the engine to turn and propel a drive shaft. Insulated with ceramic to make sure the electric charge flowing through it is properly discharged, the plug is screwed into the cylinder head. The movement of the piston sucks fuel into the cylinder until it reaches the optimum level, the compression triggering the spark plug to send a pulse that ignites the fuel and pushes the piston to the back of the cylinder. This process is repeated hundreds of times a minute in an internal combustion engine. Eventually spark plugs simply wear out, particularly if they are not properly gapped, if the fuel mixture is improper, or the engine is subject to excessive use. This plug is compatible with most lawnmowers, small engines, and pressure washers made by Briggs & Stratton, Cub Cadet, and Toro. The plug itself is a guaranteed OEM part and is sold individually.

Engine won't start? A worn pawl friction plate in the starter assembly prevents cranking. This small engine part transfers power to the starter cup.

The breather tube is responsible for filtering out exhaust gases from the crankcase. It has special fibers in the tube to remove contaminants as it moves the exhaust gases through the ventilation valve and out into the air. The tube also helps ensure that the engine air stays cool for optimal performance. This rubber tube can become dry and cracked over time, or it could be damaged due to an incident or impact. In any case, the tube should be fully replaced when it is not functional to ensure optimal performance at all times. This genuine OEM breather tube is manufactured to exact standards and made by Briggs and Stratton. It is compatible with select engines on more than 150 lawn mowers and generators from Toro, Briggs & Stratton, and Lawn Boy. This replacement tube is made of high-quality materials and sold as an individual part. No hardware or other parts are included with the purchase. This part should only be replaced once the engine is cool and all work should be done in a well-ventilated area. A screwdriver and socket set will be required to replace this part.

Secures engine components on gas line trimmers. Replace this mounting nut if it's stripped, corroded, missing, or no longer holds parts firmly in place.

Replacement screw that secures the pawl friction plate in lawn and garden engines. Replaces lost, stripped, or damaged flange bolts on the recoil assembly.

Engine won't shut off when you turn the key? Replace your lawn mower's stop switch to restore safe engine control. Simple safety repair.

Engine won't start or runs rough? A cracked or missing spark plug boot causes misfiring and prevents proper ignition. Easy DIY replacement part.

This is an authentic muffler deflector screw that is found in small engines for outdoor power equipment from Briggs & Stratton. This metal screw is designed to secure the muffler deflector to the flywheel. In select models, it may also be used to secure the starter clutch to the flywheel. The screw is durable but exposed to high heat and constant wear, which means that it can become damaged or worn with regular use. If the screw is lost or damaged, it will need to be replaced. It should always be replaced with a genuine OEM part. This OEM muffler deflector screw is manufactured by Briggs & Stratton to exact standards and is compatible with several models of small engines. It can be used with various models of blowers, pressure washers, generators, and snow throwers from Toro, Murray, and Briggs & Stratton. It is sold as an individual replacement part. To replace this screw, the flywheel cover will need to be removed. Then, if it is still present, the old screw will need to be removed and the new one can be installed. This screw requires a hex or Torx screwdriver to install. Always wear gloves and disconnect the spark plug for safety when performing engine repairs.

This screw is designed to be used on all sorts of lawn and garden equipment. The metal screw is durable and attaches to the muff guard bracket to keep it in place and stable while the equipment is being used. This screw can become damaged through overuse or wear and tear. It can also break or become stripped, which will require it to be replaced.Visually inspecting the area with the muff guard bracket is connected to the rest of the equipment will give information about whether the screw is broken or damaged. The screws can also be cleaned to be more visible so small problems are easier to pick up on. Sometimes the screws can become loose, which is another situation where a replacement is needed. Simply use a screwdriver to take out the old screw and replace it with a new one.This screw is a genuine OEM replacement part that is directly sourced from the manufacturer. It comes as an individual part. The screw can be used on snowblowers, lawnmowers, lawn tractors, tillers, pressure washers, leaf blowers, edgers, generators, wood chippers, and log splitters made by MasterCut, Simplicity, MTD, Snapper, Lawn-Boy, Wheel Horse, Cub Cadet, Toro, Craftsman, and Briggs & Stratton.

Fix a stretched or broken starter rope spring with this friction spring. Prevents pulley damage and overstretching. Fits small engines on snow throwers, pressure washers, and generators. Easy DIY repair.

Rocker arm stud for lawn and garden engines. Secures the rocker arm to the cylinder head. Replace if stripped, broken, or missing for proper assembly.

If your small engine won't start or has no spark, a faulty spark plug terminal may be the cause. This terminal connects the ignition coil to the plug.

This spring brake is a genuine Midwest Engine part that can be used as a replacement part for outdoor appliances with small engines, including lawn mowers, chipper shredders, snowblowers, and other such appliances. Spring brakes are a braking system employed a large, coiled spring that is kept under high tension; the control valves attached to the spring brake are the mechanism by which the spring brake is released.If the spring brake has been damaged, is malfunctioning, or is in a state of disrepair, this will manifest in the form of a sudden, volatile eruption from the air brake chamber. This is a dangerous state for a small engine, so repair should be conducted immediately. Additionally, a new spring brake part should be ordered before any attempt to use the appliance without a proper repair. Remember to always wear gloves when handling, repairing, and operating outdoor equipment, and stay safe around the small engine of the appliance if the spring brake has malfunctioned and caused a dangerous situation.This spring brake is compatible with the brands Briggs and Stratton, Cub Cadet, and Toro.

Air cleaner primer base for lawn and garden engines. Installs on the carburetor air cleaner assembly. Replace if cracked, broken, or missing.

Foam pre-cleaner filters dirt before it reaches your engine's main air filter. Replace when clogged or damaged to maintain airflow and engine performance.

This OEM air cleaner cover from Briggs & Stratton fits over the air cleaner and filter system, protecting the filters from excess dirt, debris, and other potential damage. This cover is also designed to help hold the air filter in place. The plastic housing is durable, but it can be subject to damage over time. This replacement is a snap-on cover, so no tools are required. Be sure to wear gloves when performing any kind of work on lawn and garden equipment. This air cleaner cover is designed to work with multiple types of lawn and garden equipment from Briggs & Stratton, Lawn-Boy, and Toro. It works with various engines on generators and lawnmowers, including hundreds of different specific models. It is sold individually and does not include the actual air filter or the bottom part of the housing.