21AK125G800 MTD Tiller - Overview

A carburetor basically consists of an open pipe through which the air passes into the inlet manifold of the engine. The pipe is in the form of a Venturi: it narrows in section and then widens again, causing the airflow to increase in speed in the narrowest part. Below the Venturi is a butterfly valve called the throttle valve ' a rotati...Read moreng disc that can be turned end-on to the airflow, so as to hardly restrict the flow at all, or can be rotated so that it (almost) completely blocks the flow of air. This valve controls the flow of air through the carburetor throat and thus the quantity of air/fuel mixture the system will deliver, thereby regulating engine power and speed. The throttle is connected, usually through a cable or a mechanical linkage of rods and joints. Fuel is introduced into the air stream through small holes at the narrowest part of the Venturi and at other places where pressure will be lowered when not running on full throttle.

This is a genuine manufacturer-sourced replacement component which is specially designed for use with Bolens and Troy-Bilt tillers. The throttle cable is connected to the carburetor and it stops the engine when you shift the lever to the full choke position. It is a high-quality rubber insulated part is sold individually, please note, the housing, the trigger and the hardware are all sold separately.

This is an original replacement part sourced directly from the manufacturer. The screw is commonly found in yard equipment from Craftsman, such as lawn tractors, snow blowers, and edgers. This part is made of metal, and may be found in various locations in the machine, depending on model. Please be aware that there are different screws...Read more used in the machine. Refer to the parts diagram to be sure of ordering the correct part. You will require a wrench when replacing this item. The screw is sold as an individual replacement part.

This is an authentic Craftsman replacement part that has been sourced from the original manufacturer to be used with trimmers and blowers. The gasket is used to seal the connection between the carburetor and the air cleaner assembly. It is recommended to replace gaskets when servicing the motor to ensure proper seals when the parts are reassembled. This item is available as an individual replacement part.

This clutch assembly is a genuine OEM replacement kit for outdoor lawn equipment. The kit includes the clutch drum, clutch, clutch washer, and screw. The clutch assembly transfers power from the engine to the cutting attachment which allows you to operate the equipment. Over time, the clutch assembly may malfunction due to normal wear and...Read more tear or accidental damage. If the small clutch assembly fails, the engine will likely stall, and the cutting attachment will not be able to engage. To remove the clutch assembly, first bind the piston to prevent it from rotating. You can do this by removing the spark plug and inserting a length of rope into the cylinder with a few inches remaining outside. Remove the clutch cover and use a clutch removal tool to remove the nut that secures the assembly. Pull the old assembly from the crankshaft and position the new assembly in its place, ensuring it is securely fitted.

This is a manufacturer approved O-Ring designed for lawn and garden equipment. This is the O-Ring that provides an Air Tight seal between Carburetor and Cylinder Head. If doing maintenance on carburetor it is recommended to replace the O-Ring instead of re-using the old one. Over time rings and seals tend to dry out and would no longer provide proper seal compromising engines performance.

Also referred to as a Lock Nut or Flange Lock, this nut is designed for use with various lawn and garden equipment. The purpose of this part is to hold parts in place while resisting loosening when properly threaded. It is sold individually, not as part of a kit or assembly. It is black, made of metal, and is found in a variety of locatio...Read morens. Refer to your owners manual to determine if this is the correct part. This part will need to be replaced when it is weak or broken. The symptoms experienced when this part breaks will depend on its location. You will need pliers to complete this repair. Customers rate this repair as Easy.

This authentic manufacturer-approved component which is specially designed for use with handheld lawn and garden equipment. The purpose of this o-ring is to provide an air-tight seal between connected parts, unfortunately, over time it may wear out and begin to crack eventually requiring a replacement. Please make sure to check appropriat...Read moree diagrams of your model for the correct location and application of this o-ring. Keep in mind this high-quality item is made of durable rubber and is sold individually.

This is a genuine OEM sourced part which is specially made for use with Craftsman handheld lawn and garden equipment. Its purpose is to deliver electric current from the ignition system to the combustion chamber. It will ignite the air fuel mixture by the spark. Unfortunately, over time a spark plug can wear out or it may get damaged even...Read moretually requiring a replacement to ensure peak performance. Keep in mind this high-quality spark plug is made of durable materials and is sold individually. Please make sure to refer to the owners manual of your model for the correct location and application of this component.

This is an OEM insulator assembly that is used to protect the carburetor from engine heat and features various seals and hardware made of plastic, steel and rubber. It fits in between the carburetor and cylinder to prevent excessive heat from affecting the performance and operation of the carburetor. It is recommended that you use protect...Read moreive gloves, a screwdriver, and other tools for the replacement process, so check your model for what tools you will need for installation.