Stratified scavenging carburetor

A carburetor, including:

• a carburetor body having a scavenging air passage and an air intake passage formed therein;
• an air valve disposed in communication with the scavenging air passage and having an air valve shaft rotatably carried by the carburetor body, an air valve head carried by the air valve shaft for rotation with the air valve shaft between closed and open positions to control air flow through the scavenging air passage, and an air valve operating lever carried by the air valve shaft for rotation with the air valve shaft;
• a choke valve disposed in communication with the air intake passage and having a choke valve shaft, a choke valve head carried by the shaft for movement between an open position permitting a substantially unrestricted fluid flow therethrough and a closed position restricting fluid flow through the air intake passage, and a choke valve lever carried by the choke valve shaft for rotation with the choke valve shaft;
• a throttle valve disposed in communication with the air intake passage and having a throttle valve shaft, a throttle valve head carried by the throttle valve shaft for movement between an idle position restricting fluid flow through the air intake passage and a wide open position permitting a substantially unrestricted fluid flow therethrough, and a throttle valve lever carried by the throttle valve shaft and coupled to the air valve operating lever by a lost motion coupling enabling movement of the throttle valve away from its idle position a predetermined amount without moving the air valve from its closed position with continued movement of the throttle valve beyond said predetermined amount moving the air valve toward its open position as a function of the continued movement of the throttle valve toward its wide open position;
• and
• a lock lever rotatably carried by the throttle valve shaft, selectively engageable with the choke valve lever, and selectively engageable with the throttle valve lever so that movement of the choke valve to its closed position engages the choke valve lever with the lock lever and causes the lock lever to engage the throttle valve lever to displace the throttle valve to a start position spaced from its idle position an amount less than said predetermined amount without moving the air valve from its closed position thereby providing an enriched fuel and air mixture to the engine compared to the fuel and air mixture delivered to the engine when the throttle valve is in its idle position.

A carburetor, including:

• a carburetor body having a scavenging air passage and an air intake passage formed therein;
• an air valve disposed in communication with the scavenging air passage and having an air valve shaft rotatably carried by the carburetor body, an air valve head carried by the air valve shaft for rotation with the air valve shaft between closed and open positions to control air flow through the scavenging air passage, and an air valve operating lever rotatably carried by the air valve shaft;
• a choke valve disposed in communication with the air intake passage and having a choke valve shaft, a choke valve head carried by the shaft for movement between an open position permitting a substantially unrestricted fluid flow therethrough and a closed position restricting fluid flow through the air intake passage, and a choke valve lever carried by the choke valve shaft and engageable with the air valve when the air valve is closed and the choke valve is moved to its closed position to hold the air valve in its closed position;
• and
• a throttle valve disposed in communication with the air intake passage and having a throttle valve shaft, a throttle valve head carried by the throttle valve shaft for movement between an idle position restricting fluid flow through the air intake passage and a wide open position permitting a substantially unrestricted fluid flow therethrough, and a throttle valve lever carried by the throttle valve shaft and engageable with the air valve operating lever during at least a portion of the movement of the throttle valve between its idle and wide open positions so that when the choke valve is open engagement of the throttle valve with the air valve operating lever moves the air valve toward its open position as a function of the continued movement of the throttle valve toward its wide open position, and when the choke valve is closed, continued rotation of the throttle valve lever beyond its engagement with the air valve operating lever rotates the air valve operating lever relative to the air valve shaft without moving the air valve from its closed position.