Thus, the likelihood of introducing additional contaminants into the carburetor of an internally vented float bowl carburetor is greatly reduced. Leaks that don't permit fuel to escape but allow air to enter will also become problems, as loss of vacuum in the fuel line will lead to fuel starvation. STUDIO TORTA SOCIETA' SEMPLICE, Free format text: A carburetor (10) for providing a fuel/air mixture to an internal combustion engine, said carburetor comprising: a carburetor body (12) having a throat (47) formed therein, said throat including a fuel/air mixture passage (46) through said body, a float regulated fuel supply bowl (20) adapted to contain a quantity of liquid fuel (21) and having an airspace (25) above said fuel, a fuel nozzle (44) for conducting fuel from said bowl to said fuel/air mixture passage, characterized in that the carburetor has an air-filled variable volume primer chamber (50), a priming passageway (62) extending from said variable volume chamber to said airspace, a flexible bulb (52) forming a portion of the periphery of said variable volume chamber, said bulb being adapted to be depressed to abruptly vary the volume of said chamber and displace a discrete volume of air from said chamber through said priming passageway into said airspace, and a venting passageway (60) extending from said throat to said primer chamber, said venting passageway communicating with said primer passageway whereby said fuel supply bowl is vented to said throat. Flange 53 is retained in groove 56 by suitable sealing means such as primer bulb retainer ring 58. Internally vented bowls have a further advantage over externally vented float bowls because the air that is supplied to the vent comes from the interior of the engine, and thus has already passed through the carburetor air filter. When the outboard is running normally, the engine’s fuel pumps create a slight vacuum in the fuel hose. During a priming operation of carburetor 10, primer bulb 52 is depressed by the operator. Primer chamber 50 includes the airspace within primer bulb 52 as well as the air within recessed area 59. I will pass on this information, could be a bad check valve in primer bulb but min has a redundent check valve in the fuel line which has already been replaced. If the lines are properly installed and the fuel filter has free flow, about the only thing that will prevent the primer bulb from operating is a faulty check valve in the portion of the carb immediately below the primer bulb. FREE Shipping on orders over $25 shipped by Amazon. A priming passageway extends from the recessed area of the chamber to the airspace in the fuel supply bowl. The difference in results is amazing, and just by changing the orientation of the primer to vertical, its operation is much improved. This air exerts pressure on the fuel which forces the fuel upwardly through a conduit into the venturi, where it is mixed with air and then drawn into the intake manifold of the engine. This venting may be either internal whereby the air supply to the vent is drawn from the throat of the carburetor, or external whereby the venting air is supplied from the atmosphere external to the carburetor. Boats with on-deck fuel tanks may have the primer bulb located at the tank end of the fuel line. The carburetor of Claim 2, wherein said bulb (52) is resilient, whereby the resiliency of said bulb causes said variable volume chamber (50) to return to its pre-displaced volume. DE, Date of ref document: A primer bulb is included which helps to … 5. This application is therefore intended to cover any variations, uses or adaptations of the invention following the general principles thereof and including departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and fall within the limits of the appended claims. You have a bad check valve in the carb body. In order to attempt to eliminate this loss of priming charge, the type of internal vent that is generally found in the art is necessarily of small diameter in order to hinder this loss of the priming charge. Thus, a suitable vent is provided. Another advantage of the present invention is that it provides an internally vented bowl carburetor whereby dirt and other contaminants are not introduced into the carburetor through the vent opening. High output primer bulb-60% more output per pump than leading competitors. the pump body and out the overflow tube. The passageway is then linked to the airspace above the float bowl through the conventional primer passageway. a primer bulb to become firm. Buy 2. The sealing off of venting passageway 60 by check valve 66 prevents a loss of the priming charge through this passageway, and insures that substantially all of the priming charge passes into airspace 25 to perform useful work in forcing the fuel charge into venturi 46. Quantity: 3 or more for $3.75/ea. into the engine crankcase. The present invention, in one form thereof, further comprises a carburetor for providing a combustible fuel/air mixture to an internal combustion engine. In just a few squeezes it should be possible to fill the bulb with fuel. Therefore, it is necessary to provide a means for venting the airspace above the float bowl. In addition, a variable volume primer chamber is provided, and a priming passageway is provided that leads from the primer chamber to the fuel supply bowl. Order Primer Bulbs for your vehicle and pick it up in store—make your purchase, find a store near you, and get directions. Portions Copyright © 2003 by James W. Hebert. Last modified: If its fuel line is not primed, even an engine that is in perfect tune will will require a great deal of cranking to start. One advantage of the present invention is that it provides an effective vent for a carburetor bowl that includes a check valve so that the priming charge is not lost through the vent. New fuel lines at this point is a good idea. Fuel 21 from float bowl 20 is introduced into carburetor body 12 through, for example, one or more fill orifices 34. We have the Walbro Check Valve you need with fast shipping and low prices. In the past, certain problems have arisen with regard to the venting of the float bowl which have hindered the efficient operation of the engine. Venting passageway 60 is once again open and in communication with airspace 25, thereby providing a suitable vent for fuel bowl 20. Almost all primer bulbs consist of a flexible rubber bladder or bulb with inlet and outlet connectors. This could be a stuck float valve on a carburetor, or a fuel leak Atmospheric pressure in the tank through the vent pushes the fuel from the tank to the engine. Float bowl 20 is attached to hollow columnar portion 38 of carburetor body 12 by means of bowl nut 30 and washer 32. collapse in suction, but it will tend to lose some of the hard A primer bulb is a small rubber “button” or bulb that is pressed in order to “prime” the engine before starting. Primer limiter boss 57 is defined in pocket 54 by annular groove 56, and has a generally cylindrical recessed area 59 disposed therein as shown in Figs. 3 is a sectional view similar to Fig. The inlet and outlet fittings typically contain a hose barb and these are generally available in three sizes to fit commonly used fuel lines. If the primer bulb is oriented with the flow arrow pointing downward, gravity and the weight of the fuel in the line above the inlet check valve may spoil its operation, and the primer will not work properly. In a float bowl type of primer, such as that found in the present invention, the volume of the priming charge may be as large as the volume of air displaced from the primer bulb. Bore region 49 of carburetor body 12 form thereof, provides a carburetor 10 for a. Speeds some engine fuel pumps create a slight vacuum in the fuel.... 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