Ignition systems for portable power tools

An air filter unit for a portable power tool having a carburetor comprising:

• a housing for holding an air filter, the housing including a housing base and a housing cover for the housing base, the housing base including;
• a housing base floor including ports through which air may flow to the carburetor and means by which the housing base may be attached to the carburetor;
• a housing base perimeter wall integral with the housing base floor and extending, generally, perpendicularly from the perimeter of the housing base floor in the direction of the housing cover, the housing base perimeter wall having an inside surface and an outside surface, the inside surface of the housing base perimeter wall and the housing base floor defining a housing base interior, and the housing base perimeter wall including an anterior section, a posterior section, a first lateral section joining one terminus of the anterior section to one terminus of the posterior section and a second lateral section joining the other terminus of the anterior section to the other terminus of the posterior section such that when the housing is installed in the portable power tool the anterior section is nearest the front of the power tool, the posterior section is nearest the rear of the power tool and the first and second lateral sections are disposed toward opposite sides of the power tool;
• an augmentation integral with the first lateral section of the housing base perimeter wall, the augmentation extending, substantially perpendicularly from the housing base floor in a direction away from the housing cover;
• a pair of opposed support legs for securing the housing base to the chassis of the portable power tool, a first of the opposed support legs being integral with the augmentation and the second of the opposed support legs being integral with the second lateral section of the housing base wall;
• and
• a mounting element integral with the outside surface of the first lateral section of the housing base perimeter wall for the mounting thereon of an ignition switch for the portable power tool.