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  Sears Parts Direct is a website that supplies schematic drawings and replacement parts for all products sold by the department store. Lawn mowers sold by Sears are divided into two categories: walk-behind mowers and riding mowers/tractors. In the former category 40 brands are listed. In the latter, 43 brands are listed. Though many mowers include the same basic engine parts, each brand of mower sold by Sears has its own page on the website with diagrams and links to replacement parts.
  
  

Throttle Choke Control

• A throttle choke is a common component of small engines, such as those of lawn mowers. Poulan lawn tractor model number 96012000401, a riding mower, is one of the many lawn mowers sold by Sears with this part. A throttle choke is a combination of a throttle and a choke. According to Repair Clinic's guide to small engines, a throttle increases the speed of an engine. A choke is responsible for monitoring the amount of air and fuel injected into an engine for performance. When a riding mower speeds up, more fuel must be injected into the engine. Thus the throttle choke control accomplishes both of these tasks simultaneously.
  
  

Recitifier

• A rectifier is a common part in electrically-powered lawn mowers. The Black & Decker MM850 , an electric mower sold by Sears, is one such machine. Online resource Small Engine Information explains that a rectifier is a device that rectifies, or coverts, power from AC to DC . AC, or alternating current, operates as both a positive and negative current. DC, or direct current, alternates solely as a positive current. The model number for the rectifier built to fit Black & Decker MM850 is 72256-03.
  
  

Exhaust Gasket

• Sears lawn mowers, such as the Craftsman zero-turn rear engine rider model number 10727786 have exhaust gaskets. A gasket is a circular engine part that seals two pipes together so that liquid can flow through them. An exhaust gasket in a lawn mower allows exhaust fluid to flow from the engine, into the exhaust system, without leaking from the mower. The Sears exhaust gasket for the Craftsman 10727786, model number 1731214SM, differs in appearance from the manufacturer's product, though it performs the same function.
  
  

Ignition Coil

• The Husqvarna 55R21HVB is a walk-behind lawn mower sold by Sears that uses a Honda GCV160 engine. An integral part of this engine is the ignition coil. According to Princeton University's Word Net Web online dictionary, an ignition coil converts the current from a battery into the high-voltage currency required of a spark plug. Ignition coils designed for the Honda GCV160 engine is model number 30500-ZL8-004. The coil works in all Honda GC135, GC160, GCV135 engines, as well as 12 variations of the GCV160.