Engine start device of a rotary valve carburetor

Abstract

A compact engine start device of a combustion engine rotary-type carburetor overrides normal operation of a rotary throttle valve to provide a richer mixture of fuel-and-air to start a cold engine. Rotation of a start lever of the start device activates a releasable camming interface coupler causing the throttle lever to rotate about a rotary axis and axially lift partially out of the carburetor at prescribed angular and axial distances. This provides the engine, through a fuel-and-air mixing passage, with a controlled and enriched ratio and volume of a fuel-and-air mixture. Preferably, the start lever has a projecting rod that inserts into a hole in the carburetor body for rotation about an axis orientated substantially parallel to the rotary axis. An outward surface of the start lever is in rotational sliding contact with a low-profile, preferably cantilevered, retention arm preferably formed unitarily to a metering fuel pump cover engaged removably to the body of the carburetor, thus allowing rotational movement but preventing axial movement of the start lever. Because the start lever does not move axially to displace the rotary throttle valve, the height of the start lever is favorably minimized. Moreover, the start lever preferably has a knob for user interface at a distal end of the lever that conforms generally about the retention arm thus maximizing knob size yet not contributing to an increase in carburetor size.

Description

[0001] Related application [0002] The applicant claims the priority of Japanese Patent Application No. 2005-026219 filed on February 2, 2005. Technical field [0003] The invention relates to a rotary valve type carburetor for an internal combustion engine carburetor, in particular to an engine starting device for the carburetor. Background technique [0004] The known rotary carburetor has a fuel-air mixing passage provided to pass through a main body to allow a fuel-air mixture with a controlled ratio and volume to flow into the internal combustion engine. This control is usually achieved by a throttle valve, which moves rotatably and axially in a cylindrical cavity transverse to the mixing passage. The cylindrical part of the throttle valve arranged in the cavity has a through hole, and when rotating, the through hole is usually adjustably aligned with the mixing channel that can generally control the flow rate of the mixed gas. The cylindrical portion also supports a valve n...

AI Technical Summary

Problems solved by technology

Unfortunately, the known starting device has many parts, and the known cam surface requires a structure that protrudes further outward from the carburetor body than the throttle lever in its most axially retracted state ( wide open), thus significantly increasing the size of the carburetor

Moreover, the known starter levers have a handle or button at the end to create leverage, which also necessarily protrudes a considerable distance from the carburetor body, thereby preventing the ideal compact design of the carburetor.

Images