Walbro Engine Management, L.l.c.

Walbro Japan, Inc.

Tetsuji Kojima

Hitoshi Terakado

Masao Suzuki

Hidenori Sasaki

Masashi Sasaki

Hiroshi Nagata

A carburetor valve and limiter cap assembly for limiting adjustment of fuel flow in a carburetor may include a needle valve and a limiter cap. The needle valve may have a tip, a threaded portion, a head having a flange with an outer diameter greater than the rest of the head, and one or more serrations formed on the head. The limiter cap may have a sidewall, a tab extending outwardly from the sidewall, a first cavity having an inner diameter sized for an interference fit with the flange, and at least one driving feature to engage at least one serration so that rotation of the limiter cap causes rotation of the needle valve. The interference fit between the flange and the limiter cap inhibits removal of the limiter cap from the needle valve to prevent undesired adjustment of the needle valves by an end user.

Carburetor valve adjustment limiter

A stratified scavenging carburetor with a lost motion coupling permits limited relative movement of a throttle valve relative to an air valve so that initial opening of the throttle valve off idle does not open the air valve to avoid diluting with scavenging air the fuel and air mixture delivered to an engine. Rotation of the throttle valve beyond a predetermined amount from idle causes a corresponding opening of the air valve to provide scavenging air to the engine. Closing a choke valve engages a lock lever with the throttle valve to move the throttle valve off idle to a start position without opening the air valve. In another embodiment, closing the choke valve prevents the air valve from opening even if the throttle valve is moved beyond where the throttle valve would cause the air valve to open if the choke valve were open. Thus, a richer than normal fuel and air mixture can be supplied to the engine during a choke-assisted start and warm-up of the engine.

Stratified scavenging carburetor

Growing community of inventors

Shibata-gun, Japan

Tetsuji Kojima