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Publication numberUS3307836 A
Publication typeGrant
Publication dateMar 7, 1967
Filing dateJan 15, 1965
Priority dateJan 15, 1965
Publication numberUS 3307836 A, US 3307836A, US-A-3307836, US3307836 A, US3307836A
InventorsDonald N Arndt, Charles H Tuckey, J D Tuckey
Original AssigneeWalbro Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Manual primer mechanism
US 3307836 A
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Description  (OCR text may contain errors)

March 7, 1967- D. N. ARNDT ETAL 3,307,836


MANUAL PRIMER MECHANISM March 7, 1967 2 Sheets-Sheet 2 Filed Jan. 15, 1965 FIG-2 FIG.3

INVEN TORS DONALD N. ARNDT CHARLES H. TUCKEY B) J. D. TUCKEY g M @imzz ATTORNEYS United States Patent O 3,307,836 7 MANUAL PRIMERMECHANISM Donald N. Arnd t, Charles H. Tuckey and .I. D. Tuckey, Cass City, Mich, assignors to Walbro Corporation, Cass City, Mich, a corporation of Michigan Filed Jan, 15, 1965, Ser. No. 425,715 1 Claim. (Cl. 261-34) This invention relates to a manual primer for carburetcm and is more specifically directed to a primer for carburetors for small engines, such as are used on power lawn mowers, chain saws, go-ca rts and the like.

Very frequently the starting of an engine is difficult particularly when the engine has been used to a conside'rable extent and the ignition system is apt to be weaker than it is intended to be. difficult when an engine has been sitting for some time Without being used and gasoline has evaporated from the passages of the carburetor so that it is not immediately available to the engine manifold.

It is an object of the present invention to provide a relatively simple manual primer which can introduce gasoline into the venturi throat of the carburetor Where it will become immediately available to the engine. Briefly, this is accomplished by a pressure device which can be utilized in combination with the normal vent of the carburetor to the fuel chamber to apply momentary pressure to the surface of the fuel in the fuel reservoir forcing fuel into the carburetor jet.

Other objects and features of the invention relating to details of construction and operation will be apparent in the following description and claim.

Drawings accompany the disclosure and the various views thereof may be briefly described as:

FIGURE 1 is a sectional view of the carburetor showing the manual primer in relation to the other parts.

FIGURE 2 is a top view of the carburetor.

FIGURE 3 is a horizontal section through the carburetor.

Referring to the drawings:

A carburetor housing H has a fuel inlet 20 controlled by a needle valve 22 actuated by a lift member 24 on a standard ring float 26 pivoted at 28 in a carburetor bowl 30, the bowl being suitably sealed at 32 to the housing. A spring-pressed drain pin 34 is provided at the bottom of the bowl and a brass nipple insert 36 screws into a depending portion 38 of the housing which serves as a mount post for the float chamber shell 30, there being suitable sealing washers 48 provided. In the threaded passage above the nipple 36 is a main fuel jet stem having a threaded portion 41 and an upward extending portion 42 extending into the horizontal venturi passage 44. In the nipple 36 is a threaded needle valve 46 to control the central passage 50 of the jet 42.

Fuel reaches the jet through a short passage 52 in portion 38 of housing H leading from the flat chamber to the space between the nipple 36 and the jet base 41. A suitable idling system can be provided through passage 54 shown in FIGURE 1 and a passage 56 shown in FIG- URE 3 terminating in idle ports 58 and 60, the port 60 being controlled by a suitable needle valve 62, these ports being located adjacent the throttle valve 64. In the inlet of the venturi passage 44 is a choke valve 66 of standard construction.

The primer mechanism is mounted on a tube 7 which projects down through the housing H and through the venturi passage 44 into the top of the float bowl chamber as shown in FIGURE 1. The end opening 72 of the tube 70 is positioned above the normal liquid level in the float bowl. Mounted on the tube 70 by a sleeve 74 is a small cup-like chamber 76 having a round de- The starting is also pending projection 77 which is firictionally engaged with the sleeve 74, the other end of the sleeve being frictionally engaged with the top of tube 70. The cup 76 has a flange 78 and is capped by a cover 80 which is preferably of such material as a resilient plastic so that it may have a snap-on connection.

Within the cup 76 is a plunger P formed of a disc 82 and a disc 84 which lie on either side of the center of a resilient sealing member 86, the sides of which extend beyond the disc 84 to contact, in a slidable sealing relation, the cylindrical walls of the cup 76. A small button 88 having an enlarged flange 90 at the bottom is captive within the cup and cover and is projected outwardly by (reason of the compression spring 92 seated on the bottom of the cup 76 and located on a small projection 94 on disc 82. This piston assembly can be made in various ways. One preferred embodiment comprises forming the button 88 as a unit and assembling the perforated sealing member 86 and perforated discs 82 and 84 over the projection 94 in frictional engagement. A small opening 96 in the wall of the cup normally vents the top of the float bowl chamber to atmosphere through the cup 76 and the tube 70.

In the operation of the manual primer, it will be seen that when the button 88 is pressed downwardly against the action of the spring 92, the atmospheric vent 96 will first be closed by the downward movement of the plunger P and then pressure will develop in the cup which is transmitted through tube 70 to the surface of the fuel in the float bowl. This will cause it to squirt into the passage 52 and up through the jet passage 50 into the Venturi, thus providing an immediate supply of fuel for engine starting. Repeated operation of the button will supplement this fuel injection and the engine being supplied may be readily started with an ample supply of fuel.

It will thus be seen that with a very simple mechanism to apply air pressure to the surface of the fuel in the float chamber, supplemental fuel may be supplied to the venturi passage of the carburetor.

We claim:

In a carubertor for furnishing fuel to the intake manifold of an internal combustion engine and of the type having a fuel supply chamber connected to a venturi passage, an improvement for introducing supplemental fuel into said venturi passage comprising:

(a) a rigid tube mounted in said carburetor and projecting upwardly therefrom, said tube having a connection to the top of a fuel supply chamber above the normal fuel level in said chamber,

(b) a cup mounted on and supported by said tube having a depending hollow projection pneumatically associated with the interior of said tube, said cup having a lipped upper edge,

(0) an apertured cap for said cup having a peripheral flange to snap over the lipped edge of said cup, and

(d) a piston in said cup retained therein by said cap and having a button projection extending through said cap, said piston being biased outwardly wherein it may be reciprocated to create above atmospheric pressure in said tube.

References Cited by the Examiner UNITED STATES PATENTS 2,827,272 3/1958 Phillips 261-41 FOREIGN PATENTS 594,982 9/1925 France. 598,578 12/1925 France.

5,551 1/1916 Great Britain.

HARRY B. THORNTON, Primary Examiner.

T. R. MILES, Assistant Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2827272 *May 27, 1955Mar 18, 1958Tillotson Mfg CoCharge forming device
FR594982A * Title not available
FR598578A * Title not available
GB191505551A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3430933 *Dec 14, 1967Mar 4, 1969Melvin C TaggartPrimer attachment for carburetors
US3451383 *Oct 31, 1967Jun 24, 1969Tecumseh Products CoCarburetor primer and throttle control mechanism
US4197825 *Nov 25, 1977Apr 15, 1980Tecumseh Products CompanyPrimer bulb retainer
US4203405 *Nov 25, 1977May 20, 1980Tecumseh Products CompanyPrimer
US4411844 *Feb 11, 1982Oct 25, 1983Outboard Marine CorporationPriming system for a vented bowl carburetor
US4512884 *Jun 14, 1982Apr 23, 1985Lucas Industries, PlcFuel treatment device
US4679534 *Feb 25, 1986Jul 14, 1987Tecumseh Products CompanyPrimer for float-type carburetors
US4776988 *Oct 13, 1987Oct 11, 1988Neal Patrick JManually changing orifice size of main metering jets
US4803963 *Apr 11, 1988Feb 14, 1989Brunswick CorporationAutomatic priming system for a marine engine
US4811901 *May 26, 1987Mar 14, 1989Curtis Dyna-Products CorporationPulse fog generator
US4926808 *Jun 8, 1989May 22, 1990Tecumseh Products CompanyPrimer bulb check valve system for an internally vented bowl primer carburetor
US5034163 *Dec 4, 1987Jul 23, 1991Outboard Marine CorporationModular side-draft carburetor
US5057249 *Jun 14, 1990Oct 15, 1991Outboard Marine CorporationCarburetor float chamber drain device
US5128071 *Feb 6, 1991Jul 7, 1992S & S Cycle, Inc.Carburetor
US5154112 *Jan 5, 1989Oct 13, 1992Wettern Laurence PAeration of liquids
US6029619 *Feb 4, 1998Feb 29, 2000Briggs & Stratton CorporationRemote primer
US6557833Oct 20, 2000May 6, 2003Briggs & Stratton CorporationPriming system for an engine carburetor
US6840508Oct 30, 2003Jan 11, 2005Tecumseh Products CompanyPush button air primer for carburetor
US6848680Mar 27, 2003Feb 1, 2005Tecumseh Products CompanyPush button air primer for carburetor
US6863266Mar 13, 2003Mar 8, 2005Tecumseh Products CompanyPush button air primer for carburetor
US7798474Mar 5, 2008Sep 21, 2010Curtis Dyna-Fog, Ltd.Ignition system for a pulse fog generator
US8006959Aug 20, 2010Aug 30, 2011Curtis Dyna-Fog, Ltd.Ignition system for a pulse fog generator
US8123198Jul 26, 2011Feb 28, 2012Curtis Dyna-Fog, Ltd.Ignition system for a pulse fog generator
EP0234097A2 *Nov 6, 1986Sep 2, 1987Tecumseh Products CompanyPrimer for float type carburettors
U.S. Classification261/34.1, 123/179.9, 261/DIG.800, 261/73
International ClassificationF02M1/16
Cooperative ClassificationF02M1/16, Y10S261/08
European ClassificationF02M1/16
Legal Events
Apr 9, 1991ASAssignment
Effective date: 19910325