A carburetor with a fuel adjustment tamperproof valve assembly and specialized tools for adjusting the valve assembly. A needle valve is received in a recess in a carburetor body with a passage open to the exterior of the body and a cylindrical surface of the passage. A valve head with a cylindrical exterior surface is received in the passage with a slight clearance between them. The specialized tools are engageable with the head to adjust the valve by rotating it.

A carburetor with a fuel adjustment tamperproof valve assembly and specialized tools for adjusting the valve assembly. A needle valve is received in a recess in a carburetor body with a passage open to the exterior of the body and a cylindrical surface of the passage. A valve head with a cylindrical exterior surface is received in the passage with a slight clearance between them. The specialized tools are engageable with the head to adjust the valve by rotating it.

This invention relates to an anti-adjusting butterfly valve type carburetor, comprising a kind of high speed adjustment oil needle having eccentric hole and a kind of idle adjustment oil needle having eccentric hole, and it also correspondingly discloses a kind of specialized adjustment tool having eccentric convex platform for adjusting the high speed adjustment oil needle and the idle adjustment oil needle. The invention also discloses a kind of high speed adjustment oil needle having eccentric convex platform and a kind of idle adjustment oil needle having eccentric convex platform an it also correspondingly discloses a kind of specialized adjustment tool having eccentric hole for adjusting the high speed adjustment oil needle and the idle adjustment oil needle. Compared with the prior art, the invention has the following beneficial effects: Because the high speed adjustment oil needle and the idle speed adjustment oil needle have the anti-adjusting structure, thereby ensure that the customers can not be adjust the oil flow into the carburetor freely, and then ensure that the engine is always in optimal setting state.

This invention relates to an anti-adjusting butterfly valve type carburetor, comprising a kind of high speed adjustment oil needle having eccentric hole and a kind of idle adjustment oil needle having eccentric hole, and it also correspondingly discloses a kind of specialized adjustment tool having eccentric convex platform for adjusting the high speed adjustment oil needle and the idle adjustment oil needle. The invention also discloses a kind of high speed adjustment oil needle having eccentric convex platform and a kind of idle adjustment oil needle having eccentric convex platform an it also correspondingly discloses a kind of specialized adjustment tool having eccentric hole for adjusting the high speed adjustment oil needle and the idle adjustment oil needle. Compared with the prior art, the invention has the following beneficial effects: Because the high speed adjustment oil needle and the idle speed adjustment oil needle have the anti-adjusting structure, thereby ensure that the customers can not be adjust the oil flow into the carburetor freely, and then ensure that the engine is always in optimal setting state.

An adjustment device for a carburetor adjustment valve includes a limit cap and a sleeve to prevent over-operation and destruction. The limit cap having first and second projecting parts formed in the insertion hole. The first projecting part engages a first groove on the shaft part of the adjustment valve to hold the limit cap in a first position where the limit cap and adjustment valve rotate freely relative to the sleeve. The second projecting part holds the limit cap in a second position pushed in from the first position where the adjustment valve having a limited range of rotation. The limit cap has an outer circumferential locking part formed on the outer circumference and the sleeve has an inner circumferential locking part formed on its inner circumference. In the second position, the inner circumferential locking part locks the outer circumferential locking part and prevents rotation of the limit cap.

A carburetor achieves better emission characteristics while improving a combustion state by increasing a delivery ratio of a stratified scavenging engine and reducing intake resistance. No dividing wall is provided between a throttle valve 204 and a choke valve 242, and a gap 244 between the valves 204 and 242 is opened. Intake air in both of an upper region and a lower region of the choke valve 242 flows into an air-fuel mixture passage 246 in a lower region of the fully-open throttle valve 204. A main nozzle 202 is arranged so as to be inclined toward the throttle valve 204.

A carburetor achieves better emission characteristics while improving a combustion state by increasing a delivery ratio of a stratified scavenging engine and reducing intake resistance. No dividing wall is provided between a throttle valve 204 and a choke valve 242, and a gap 244 between the valves 204 and 242 is opened. Intake air in both of an upper region and a lower region of the choke valve 242 flows into an air-fuel mixture passage 246 in a lower region of the fully-open throttle valve 204. A main nozzle 202 is arranged so as to be inclined toward the throttle valve 204.

A carburetor with rotary valve includes an idle adjustment needle with an eccentric hole, accordingly a special adjustment tool used for idle adjustment needle has an eccentric boss; a carburetor with rotary valve includes an idle adjustment needle with an eccentric boss, accordingly a special adjustment tool used for idle adjustment needle has an eccentric hole. The idle adjustment needle must be cooperated with the special adjustment tool to carry out the adjustment, thus non-professional user can not casually adjust the fuel oil needle without the special tool, so that the engine can be maintained in the best setting condition to ensure the engine exhaust to meet the environmental protection requirement.

A carburetor with rotary valve includes an idle adjustment needle with an eccentric hole, accordingly a special adjustment tool used for idle adjustment needle has an eccentric boss; a carburetor with rotary valve includes an idle adjustment needle with an eccentric boss, accordingly a special adjustment tool used for idle adjustment needle has an eccentric hole. The idle adjustment needle must be cooperated with the special adjustment tool to carry out the adjustment, thus non-professional user can not casually adjust the fuel oil needle without the special tool, so that the engine can be maintained in the best setting condition to ensure the engine exhaust to meet the environmental protection requirement.

To allow an intake negative pressure to directly act on a fuel outlet formed on a nozzle tube, and to guide a fuel discharged from the fuel outlet in the nozzle tube to the fuel-air mixture passage. A rotary carburetor (200) has a guide plate member (42) downstream of a fuel outlet (30) located in a through-hole (14). The guide plate member (42) has both side edges (42b) away from an inner wall surface (14a) of the through-hole (14). The through-hole (14) is divided by the guide plate member (42) into a first passage portion (44) and a second passage portion (46). The first passage portion (44) communicates through a piston groove with a scavenging passage of a cylinder. The fuel discharged from the fuel outlet (30) is guided by the guide plate member (42) to the second passage portion (46) and is supplied through the second passage portion (46) to a fuel-air mixture passage (24) of an engine intake system.