Carburetor

Claim 1

A carburetor comprising a mixture conduit having an air inlet and a mixture outlet, a throttle disposed in said mixture outlet for controlling flow therethrough, an air valve disposed in said air inlet for measuring air flow therethrough, a fuel passage entending to said mixture conduit for supplying fuel thereto, a metering orifice disposed in said fuel passage, a metering rod disposed in said metering orifice for controlling fuel flow therethrough, a lever positioning said metering rod, a link extending from said air valve to said lever for moving said lever and said metering rod to control fuel flow through said metering orifice in accordance with air flow through said air inlet, said lever having a slot receiving said link, and means for varying the position of said link in said slot to vary the travel of said metering rod in said orifice for selected movement of said air valve, said means including a reciprocable plunger connected to said link, a ferrule surrounding said plunger, said plunger having an adjusting screw received in one end of said ferrule for varying the relative positions of said plunger and said ferrule, a wall, an adjustable stop supported in said wall and surrounding said ferrule, said ferrule having a head engageable with one end of said adjustable stop, spring means biasing said head into engagement with said end of said adjustable stop, stop means engageable with the opposite end of said ferrule for limiting travel of said ferrule away from said adjustable stop against the bias of said spring means, a diaphragm engaging said one end of said ferrule and cover means surrounding said one end of said ferrule and the opposite end of said ferrule for limiting travel of said ferrule away from said adjustable stop against the bias of said spring means, a diaphragm engaging said one end of said ferrule and cover means surrounding said one end of said ferrule and the opposite end of adjustable stop and defining a chamber enclosed by said diaphragm and subjected to the pressure in said mixture conduit downstream of said throttle, whereby when said pressure is below a selected level said diaphragm may displace said ferrule and said plunger against the bias of said spring means to engage said ferrule with said stop means and to move said link in said slot to provide an enriched air-fuel mixture, whereby when said pressure is above said selected level said spring means may displace said ferrule, said diaphragm and said plunger to engage said ferrule head with said adjustable stop and to move said link in said slot to provide a lean air-fuel mixture, and whereby said air-fuel mixtures may be adjusted by removing said cover means and said diaphragm to expose said one end of said ferrule and said opposite end of said adjustable stop, by adjusting the position of said adjusting screw relative to said ferrule, and by adjusting the position of said adjustable stop relative to said wall.