Abstract: A carburetor having an idle nozzle and a main nozzle each with a fixed flow area and an idle speed single adjustment screw adjustable by the user. The idle and high speed fuel flows are controlled by the idle nozzle and the main nozzle, respectively. The user can adjust the engine speed only by adjustment of the idle speed adjustment screw which changes the position of the carburetor throttle valve to control the flow through the carburetor. This provides a more consistent fuel and air mixture to improve the performance of the engine and better control engine emissions by preventing the user from changing the fuel and air ratio to a mixture which is either too lean or too rich for the steady and low level exhaust emission operation of the engine.

Abstract: A fuel mixture adjusting and limiting device for a carburetor has a body received in a bore of the carburetor and defining a fuel passage through which liquid fuel is supplied to the high and/or low speed system of the carburetor, an inlet opening in the body through which fuel enters the fuel passage from a metering chamber of the carburetor and a metering pin slidably carried by the body and capable of at least partially restricting the flow of fuel through the inlet opening to control the flow rate of fuel through the body. An adjustment screw threadably received in the bore of the carburetor is rotatable to axially displace the adjustment screw and during at least a portion of the axial range of movement of the adjustment screw, the adjustment screw bears on the metering pin to axially displace the metering pin and thereby control the flow area of the inlet opening.

Abstract: Improvement in peanut clip limiter cap holder, wherein the clip spring legs are interconnected by a spring web that flexes to accommodate flexing of the clip legs free ends during insertion of the associated limiter caps into the retaining clip, and prolongs the effective friction grip service life of the clip. Optional detent dimples on the clip spring legs and cooperative limiter cap grooves enhance yieldable retention of the caps in the clip and the clip on the needle valves. When the peanut clip is used to install only a single limiter cap on a single needle valve, a dummy stud is mounted to the carburetor in the vacant needle valve position and the stud head occupies the vacant limiter cap position in the clip. An improved needle valve is made as an assembly of a lathe-turned tip/shank part and a separate precision die cast head part.

Abstract: In a first aspect, a carburetor fuel adjusting device that facilitates control of the quantity of fuel that flows from the fuel chamber to an air intake port of a carburetor by making it possible for the user to adjust an adjustment valve within the limits defined by emission control regulations. The carburetor fuel adjusting device has a cap having two appendages, and an engagement area to engage a valve extension of the fuel adjustment valves of a carburetor. The cap is retained by the retainer in either a disengaged position, or an engaged position wherein the engagement area of the cap becomes attached to the valve extensions. In the engaged position, the adjustment valves can be turned in unison with the cap within a range formed by the angle between the appendages which, when rotated, abut against stoppers.

Abstract: In a first aspect, a carburetor fuel adjusting device that facilitates control of the quantity of fuel that flows from the fuel chamber to an air intake port of a carburetor by making it possible for the user to adjust an adjustment valve within the limits defined by emission control regulations. The carburetor fuel adjusting device has a cap having two appendages, and an engagement area to engage a valve extension of the fuel adjustment valves of a carburetor. The cap is retained by the retainer in either a disengaged position, or an engaged position wherein the engagement area of the cap becomes attached to the valve extensions. In the engaged position, the adjustment valves can be turned in unison with the cap within a range formed by the angle between the appendages which, when rotated, abut against stoppers.

Abstract: A fastening member made of an elastic material is press-fitted in a gapless manner in an insertion hole that divides screw holes in a carburetor body into forward and rearward sections. Screw rods of adjustment valves are screwed into the screw holes and through screw through-holes formed in the fastening member. The screw through-holes have female screw-threads formed by thread rolling. The female screw-threads maintain pressing contact with the surfaces of male screw-threads on the screw rods as a result of the elastic recovery force of the female screw-threads, so that rattling and fuel leakage tend to be prevented.

Abstract: A carburetor adjustment screw apparatus includes an adjusting screw (2) having a shaft (7) in screw threaded engagement with a carburetor body (4) and a head (8) by which the shaft may be rotated. A generally tubular open-ended housing (10) surrounds the head of the screw and a ring (11) is rotatably mounted in the open end of the housing. Stop means (19/20) limit the angular range of rotation of the ring. A plug (12) is mounted in the ring and engages the screw such that rotation of the plug effects corresponding rotation of the screw. The plug is movable relative to the ring between a first axial position wherein the plug can rotate independently of the ring and a second axial position wherein the plug engages the ring for co-rotation therewith such that the angular range of rotation of the plug is limited to the angular range of rotation of the ring.

Abstract: In a first aspect, a carburetor fuel adjusting device that facilitates control of the quantity of fuel that flows from the fuel chamber to an air intake port of a carburetor by making it possible for the user to adjust an adjustment valve within the limits defined by emission control regulations. The carburetor fuel adjusting device has a cap having two appendages, and an engagement area to engage a valve extension of the fuel adjustment valves of a carburetor. The cap is retained by the retainer in either a disengaged position, or an engaged position wherein the engagement area of the cap becomes attached to the valve extensions. In the engaged position, the adjustment valves can be turned in unison with the cap within a range formed by the angle between the appendages which, when rotated, abut against stoppers.

Abstract: A needle valve limiter cap of single-stage and two stage types having a hollow cylindrical outer body of rigid material, carrying a limiter arm. A spring steel hollow retainer clip sleeve is telescopically received in the body and has inwardly and outwardly protruding resilient barbs reversely oriented relative to one another to respectively engage the cap body and the needle valve shank to respectively prevent retrograde relative telescopic motion between the clip and the body and between the clip and valve shank. Easy seating of the single or two-stage caps into their locked first and/or second stage needle adjustment positions also produces an audible click and feel as the inwardly protruding spring barb(s) snap into a needle shank groove or grooves. A cap living-hinge type anti-tamper flap at the cap end prevents access of any adjustment tool to a needle valve head.

Abstract: A fuel regulating method and mechanism for a rotary throttle (barrel-type) carburetor which prevents an end-user A/F adjustment that would cause increase in fuel quantity to a level in excess of a regulated value so as to comply with the exhaust gas emissions regulations. A cylindrical throttle valve having a throttle hole is disposed in an air intake passage of the carburetor body 12, the air flow is controlled by rotation of the throttle valve and the fuel flow is controlled by the position of a fuel regulating needle, attached to the throttle valve, relative to a fuel jet port of a fuel supply pipe in the carburetor body due to axial movement of the throttle valve. A bypass passage is provided within the carburetor body to communicate the throttle valve hole and fuel jet area with the air intake passage upstream of the throttle valve.

Abstract: A limiter of the extent of adjustment of a fuel metering needle valve of a carburetor for an internal combustion engine. The limiter has a housing with a passage in which the head end of the needle valve is received and a cap received in the passage on the head end of the valve for rotation in unison with the valve. An arm carried by the body of the cap is engagable with a stop in the passage to limit to less than one complete revolution the extent to which the cap and needle valve can be rotated by an end user to adjust the needle valve. To provide a tamper-resistant limiter, the head of the cap is received in a bore of the housing passage with either only a slight clearance between them or an interference fit which also inhibits rotation of the valve by vibration of the operating engine on which the carburetor and limiter are utilized.

Abstract: A carburetor fuel adjusting device that facilitates control of the quantity of fuel that flows from the fuel chamber to an air intake port of a carburetor by making it possible for the user to adjust an adjustment valve within the limits defined by emission control regulations. The carburetor fuel adjusting device has a cap having two appendages to limit its turning in the lean mixture direction and in the rich mixture direction, and an engagement area to engage a valve extension of the fuel adjustment valves of a carburetor. The valve extensions are inserted through insertion holes of a retainer attached to the carburetor body. When the cap is retained by the retainer in a disengaged position, wherein the engagement area is not attached to the valve extensions of the fuel adjustment valves, the adjustment valves can be adjusted separately from the cap. The cap, however, can be moved forward to an engaged position wherein the engagement area of the cap becomes attached to the valve extensions.

Abstract: A carburetor in which no deviation or change occurs in the adjusted position of a fuel regulating needle valve and when a cap for limiting the adjustment is mounted on the fuel regulating valve the cap cannot be intentionally broken or removed. A flow area of a fuel pasage of a carburetor body is adjusted by a needle valve received in a threaded hole in the body. Adjacent the threaded hole the carburetor body has a cylindrical cavity having a larger diameter than that of the threaded hole. A larger-diameter threaded portion is provided on the needle valve adjacent its head. A stop ring in contact with a shoulder in the cylindrical cavity is fitted on the larger-diameter threaded portion of the valve. A cup-shaped cap is fitted on the serrated head of the fuel regulating valve. An axial protrusion formed on the outer peripheral wall of the cap is engaged with an axial groove opening into the peripheral wall of the cylindrical cavity.

Abstract: A fuel adjustment screw apparatus for a diaphragm-type carburetor comprises a screw member (4) having a shaft (4a) and a head (12) by which the shaft may be rotated, with a generally tubular open-ended housing (9) surrounding the head of the screw member. A cap member (10) is mounted in the housing and is movable axially of the screw member between a first position (as seen in FIG. 1) and a second position (FIG. 2). The cap member is held clear of the head of the screw member in the first position so that the screw member can rotate freely, and engages over the head of the screw member in the second position for rotation with the head. The housing has stop means (20) which is engaged by the cap member in the second position for limiting the angle of rotation of the head.

Abstract: A carburetor fuel adjusting limit device that facilitates control of the quantity of fuel that flows from the fuel chamber to an air intake port of a carburetor by making it possible for the user to adjust a fuel adjustment valve within the limits defined by emission control regulations. The limit device has a cap that comprises an engagement area to engage a valve extension of the fuel adjustment valve and radially extending appendages to limit rotation. The construction of the engagement area, which includes axial and radial locks, enables the cap to be pressed onto the valve extension with a relatively low amount of force. The fuel adjustment valve includes a screw head attached to the valve extension and constructed to break away from the valve extension at a torque that exceeds about 8 kg-cm. A retainer is utilized to retain the cap in a disengaged position adjacent the valve extensions. Once the cap is pressed onto the valve extension the cap and the fuel adjustment valve rotate as a unit.

Abstract: A limitation device which limits post-adjustment rotation of an adjustment screw (10) on single adjustment screw carburetors (20). In one embodiment, the limitation device uses a limiter cap (100, 200) removably attached to the adjustment screw (10) which works in conjunction with a limiter stop (300, 400) attached to the carburetor. In a second embodiment, the limitation device uses a limiter cap (700) removably attached to the adjustment screw (10) which works in conjunction with a plate (600) attached to the carburetor. In either embodiment, the limiter cap (100, 200, 700) presents a first and second rotational stop (110, 210) which cooperates with at least one rotational stop (304, 306, 404, 406, 606) on the limiter stop (300, 400) or plate (600). A special tool and method is also disclosed for installing and removing the device from the carburetor.

Abstract: A cap and method for limiting the range of adjustment of a fuel flow metering valve in a carburetor. The cap has a body with an arm projecting generally radially outwardly therefrom to abut against a stop carried by the carburetor to limit valve rotation and a passage therein for telescopically axially receiving the head end of a shank of the valve. Portions within the passage enable the cap to be retained in the shank of the valve in a freely rotating first position during assembly and arm orientation, and in a second position securing the cap to the valve to limit adjustment and maintain emissions calibration. Preferably, the cap may also be moved to a third position to releasably drivingly engage the valve to perform fuel flow adjustment before securing the cap to the valve. The cap can also be prepositioned angularly relative to an adjusted position of the valve before it is moved to its second position on the valve to limit the extent of subsequent adjustment of the valve.

Abstract: A temperature compensated carburetor having a fuel metering system including a variable restriction needle gate valve for varying the effective flow cross-sectional area of the main and/or idle fuel supply duct to modulate the flow rate of fuel to the carburetor venturi mixing passage. The needle gate valve is made of plastic material having a much greater coefficient of expansion than the aluminum carburetor body in which it is adjustably mounted such that differential linear expansion and contraction of the needle valve relative to the carburetor body in response to ambient temperature changes varies the flow-controlling cross-sectional area of the fuel duct inversely relative to ambient temperature changes. The needle valve is a rod-like body with a threaded cylindrical mounting portion at one end threadably secured in a threaded bore in the carburetor body.

Abstract: A tamper-proof adjustment screw arrangement for a vehicle fuel supply system for preventing tampering with the setting of an adjustment screw that is situated in a common recess with a component requiring the availability of continued access. In a preferred embodiment, a tamper-proofing shield coacts with the configuration of a portion of a recess having a stepped bottom wall and with a spanner jam nut on the adjustment screw to create a press fit mounting of the shield that makes it exceedingly difficult to pry off the tamper-proofing shield. As an additional safeguard, the spanner nut is designed to require a special tool for loosening thereof.

Abstract: A tamper-resistant seal is disclosed for discouraging unauthorized access to an adjusting screw located in a fuel injection pump. The seal includes a bracket secured by one-way fasteners to the pump and is positioned adjacent to the adjusting screw. The bracket also includes a stud projecting outwards from its outer surface. A cover having an aperture formed therein is positioned over the bracket such that the stud passes through the aperture. When so aligned, the cover will completely enclose the one-way fasteners and the adjusting screw thereby preventing access to them. The cover is secured to the bracket by a fastener which locks onto the stud. The fastener prevents the removal of the cover from the bracket without physically destroying the seal. Such a seal is beneficial in providing visual assurance to the manufacturer that his pump has not been tampered with.

Abstract: A fuel metering apparatus, for supplying metered fuel to an associated combustion engine, has an idle fuel metering and supply system comprising adjustable valving means which, in turn, comprises a discharge orifice means and cooperating valving member which is adjustably selectively positioned with respect to such orifice means in order to thereby establish a desired metered rate of fuel flow through the thusly determined effective flow area of the orifice means for a particular pressure differential thereacross; the adjustable valving member is generally contained within a cooperating body member or portion and access to the valving member, subsequent to it being selectively positioned, is prevented by a closure member or sealing plug placed in position after the said selective positioning of said valving member; the sealing plug is formed as by a hardened metal disc and caged within a body which body is held by the cooperating body member containing the valving member; relative rotation as between the cagi

Abstract: A fuel metering apparatus, for supplying metered fuel to an associated combustion engine, has an idle fuel metering and supply system comprising adjustable valving means which, in turn, comprises a discharge orifice means and cooperating valving member which is adjustably selectively positioned with respect to such orifice means in order to thereby establish a desired metered rate of fuel flow through the thusly determined effective flow area of the orifice means for a particular pressure differential thereacross; the adjustable valving member is generally contained within a cooperating body member or portion and access to the valving member, subsequent to it being selectively positioned, is prevented by a closure member or sealing plug placed in position after the said selective positioning of said valving member; the sealing plug is formed as by a hardened metal disc and caged within a body which body is held by the cooperating body member containing the valving member; relative rotation as between the cagi

Abstract: An adjusting screw of a carburetor comprising a threaded portion, an enlarged head portion and a reduced diameter portion located therebetween. A thin hollow cylindrical wall is formed on a link lever of the carburetor. After the adjusting screw is screwed into the threaded hole of the hollow cylindrical wall, the reduced diameter portion of the adjusting screw is cut. Then, the top portion of the hollow cylindrical wall is bent inward for irremovably fixing the adjusting screw onto the link lever.

Abstract: An adjust screw device for use with a carburetor of an internal combustion engine having stops for restricting the range within which the automobile user can readjust the idle R.P.M. by adjusting the adjust screw at the carburetor. The adjust screw device is composed majorly of a first adjust screw having a large adjustable range and a second adjust screw for fine adjustment, the physical position of the second adjust screw being changed by the adjustment of the first adjust screw. After initial adjustment of the first adjust screw by the manufacturer, further adjustment of the screw is completely blocked and the second adjust screw is then adjustable by the user only over a predetermined range.

Abstract: A carburetor improvement for inhibiting tampering with a thermostatic choke coil after carburetor manufacture. A cover (3) fits over a choke coil housing (H) to enclose a choke lever, the thermostatic coil being mounted inside the cover. The cover has a circumferential flange (5) which abuts the outer surface of the housing, the flange having a notch (9) formed therein and the cover being rotatable about the outer surface of the housing to position one end of the coil relative to the choke lever. A retainer (7) locks the cover in a fixed position once the one end of the coil is located with respect to the choke lever. The retainer has a tab (11) insertable in the notch to prevent further rotation of the cover. A screw (15) having a detachable head (17) unremovably secures the retainer to the carburetor whereby once the retainer is secured, further movement of the cover is prevented.