Parts for Briggs & Stratton 121S00 (0005-2415): Sump-Engine Parts

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

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.

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.

Size: 6-32 x 3/8 inch.

Fix engine knocking or loss of power with this piston pin lock. Secures the piston pin in small engines. Essential for proper piston assembly.

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.

Intake valve for small lawn and garden engines. Replaces worn, cracked, or damaged valves affecting engine compression. Direct fit component.

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.

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.

Engine won't start, runs rough, or produces black smoke? Your carburetor mixes air and fuel for proper combustion. Common repair for lawn mower engines.

Fix engine starting problems or rough idle with this float carburetor. Direct replacement restores proper fuel delivery. Moderate DIY install in 1-2 hours.

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

Fix fuel leaks and flooding issues in your small engine with this float needle and seat kit. Stops gas from overflowing the carburetor bowl.

Replace your engine's float bowl gasket to prevent fuel leaks and ensure proper carburetor function. Install when worn, cracked, or leaking. Verify fit.

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

Fix engine starting issues with this choke return spring. Common solution when your engine won't start cold or runs rough during warmup. Easy 10-minute fix.

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 proper spacing between fasteners to prevent leaks on lawn mowers, tillers, and chipper shredders. Replace if worn or damaged.

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.

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.

This genuine rocker switch is designed as an identical replacement part for select models of blower/vacuum units. The rocker switch is also known as a power switch or on/off switch and it is what controls the current to electric blowers. The switch is made of plastic and metal. This switch may become worn and not function well after regular use because of the repetitive motion of turning the machine on and off. In some cases, the switch may experience electrical malfunctions that could present a fire hazard or keep the unit from working at all. In the event that the switch is damaged or defective, it will need to be replaced. This genuine OEM replacement rocker switch is manufactured by Briggs & Stratton. It can be used with more than 150 models of machines from Briggs & Stratton, Toro, and Vanguard. This part is made of durable plastic and metal components and is sold as an individual unit. It plugs into the pressure washer via wires, but a screwdriver may be needed to assist in the installation. Always disconnect the power supply when working on electrical components and wear gloves for safety.

This genuine Midwest Engine air filter cleaner can be used as a replacement part for the small engine of power washers. The purpose of an air filter cleaner for a power washer is to prevent the accumulation of debris, dirt, pebbles, and other such external materials that could be sucked into the engine through the air filter and cause damage to the internal components of the appliance.Air filter cleaners might have to be replaced several times within the regular lifespan of a power washer as a part of routine maintenance. If the air filter cleaner is damaged by the intake of dirt and debris or is otherwise punctured, pierced, ripped, torn, or eroded over time, the air filter cleaner should be removed immediately and replaced with this genuine OEM replacement part before using the small engine appliance again. Remember to always wear gloves when handling, repairing, and operating outdoor equipment. This is an OEM part sourced directly from the manufacturer. It is sold individually. This air filter cleaner is compatible with the following brands: Midwest Engine, Briggs & Stratton, and Troy-Bilt.

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 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.

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.

Black plastic fuel tank cap for lawn mowers, snowblowers, and pressure washers. Replace damaged, cracked, or leaking caps. Direct drop-in installation.

Float bowl for small engine carburetors. Holds liquid gasoline as a fuel reservoir. Replace if cracked, damaged, or leaking to restore proper operation.

A carburetor float bowl is an essential part of every carburetor because it controls the flow of gasoline from the fuel tank to the motor. Whether because of gasoline impurities or lots of use, the interior pieces of small engines may fail and need to be rebuilt. For that purpose, the float bowl comes with the three required gaskets. Replacing the float bowl in a Briggs & Stratton carburetor is a simple process. First, detach the carburetor from the engine, then removing the screw from the top of the carburetor housing. Replace the large gasket with the new one, making sure that it fits properly and will seal. Then set the new float bowl down onto the gasket. Next, take the small gasket and place it atop the float bowl, screwing the bolt onto the float bowl. Then it’s time to reattach the carburetor to the Briggs & Stratton engine. This OEM assembly is a factory-built replacement for the original parts it replaces. It is individually packaged and sold separately. Mowers, chippers, generators, blowers, snowblowers, tillers, and other small engines using a Briggs & Stratton engine can use this replacement kit. Among compatible brands are Craftsman, Snapper, Simplicity, Toro, Cub Cadet, and Lawn boy.