FUEL SYSTEM. Table of Contents. Section 3B - Carburetors

Transcription

1 Tle of Contents FUEL SYSTEM Section 3B - Cruretors CARBURETORS Fuel System - Trouleshooting B-2 Generl Informtion B-2 Attenutor And Cr Throttle Levers B-4 Fuel Lines B-6 Cruretor B-8 Cruretor B-10 Cruretor Fuel Circuits B-11 Flot Bowl Circuit B-11 Idle Circuit B-12 Cold Strt Circuit B-13 Off-Idle Circuit B-13 Min Circuit B-14 Bck Drft Circuit B-15 Cruretor Specifictions B-16 Cruretor Plcement nd Jet Loction for Ech Cylinder B-17 Cruretor Jet Plcement B-18 Jet Prt Numer Chrt B-18 Removing Cruretor(s) from Engine B-20 Throttle Shft Screws B-21 Flot Adjustment B-21 Instlling Cruretor(s) to Engine B-22 3 B NOVEMBER 1999 Pge 3B-1

2 Fuel System - Trouleshooting Generl Informtion Prolems, tht re thought to e cused y the fuel system, my e, in relity, something completely different. Items, tht re shown in the list on the right, could give the impression tht there is prolem in the fuel system. 1. Impeller 2. Sprk plugs 3. Ignition timing 4. Ignition sprk voltge 5. Cylinder compression 6. Reed vlves Prolem: Engine Turns Over But Will Not Strt Or Strts Hrd When Cold Possile Cuse Corrective Action Improper strting procedure used. Fuel tnk empty or too low. Improperly mixed fuel. Contminnts (wter, dirt, etc.) in fuel Fuel tnk ir vent closed or restricted. A pinched, cut or restricted fuel line. Also loose fuel line connection. Dirty or restricted fuel filter. Check proper strting procedure, s outlined in Opertion nd Mintennce Mnul. Check fuel in fuel tnk nd replce or dd whichever is necessry. Check ir vent on fuel tnk. Air vent must e open ll-the-wy nd free from ny contminnts. Check ll fuel lines nd replce s needed. Check nd tighten ll fuel line connections. Check nd replce or clen ll fuel filters. Low fuel pump pressure. Refer to Section 3A. An nti-siphon vlve. Refer to Checking for Restricted Fuel Flow in Section 3A. Choke solenoid, or enrichment vlve not operting. A needle nd set (in cruretor) tht is either stuck open or closed. Open=Flooding - Closed=Strving Improper cruretor jets, restricted jet or idle mixture screw out of djustment. Improper cruretor flot level. Check choke solenoid or vlve, nd electricl wiring to solenoid or vlve. Replce if necessry. Refer to Cruretor Disssemly in this section. Refer to Cruretor Adjustments in this section. Refer to Cruretor Adjustments in this section. Pge 3B NOVEMBER 1999

3 Prolem: Engine Idles Rough nd Stlls. Prolem: Engine Hesittes Upon Accelertion. Prolem: Engine Runs Uneven or Surges. Possile Cuse Improperly mixed fuel. Contminnts (wter, dirt, etc.) in fuel. Fuel tnk ir vent closed or restricted. A pinched, cut or restricted fuel line. Also loose fuel line connection. A dirty or restricted fuel filter. Low fuel pump pressure. Refer to Section 3A. Corrective Action CARBURETORS Check fuel in fuel tnk nd replce if necessry. Check ir vent on fuel tnk. Air vent must e open ll-the-wy nd free from restrictions. Check ll fuel lines nd replce s needed. Check nd tighten ll fuel line connections. Check nd replce or clen ll fuel filters. An nti-siphon vlve. Refer to Section 3A. A needle nd set (in cruretor) tht is either Refer to Cruretor Adjustments in this section. stuck open or closed. Open=Flooding - Closed=Strving Improper cruretor jets, restricted jet or idle mixture Refer to Cruretor Adjustments in this section. screw out of djustment. Improper cruretor flot level. Refer to Cruretor Adjustments in this section. Cruretor loose on reed lock housing. Tighten cruretor nuts securely. Reed lock housing loose, or gskets re defective. Improperly routed or restricted leed hose(s). REED VALVE SPECIFICATIONS Using pressure oil cn, spry 2-cycle oil round reed lock housing/crnkcse housing mtching surfces nd cruretor se. If engine RPM chnges, tighten or replce reed lock housing gskets or cruretor se gskets, s needed. Refer to leed line routing in this section. Reed Vlve Opening 1 -Mx in. (0.59 mm) NOVEMBER 1999 Pge 3B-3

4 Attenutor And Cr Throttle Levers Pge 3B NOVEMBER 1999

5 TORQUE REF. NO. QTY. DESCRIPTION l. in. l. ft. N m 1 1 ATTENUATOR-Sound 2 3 GASKET-Attenutor to Cr 3 6 SCREW ( x 2.500) WASHER 5 3 CAP 6 1 LEVER KIT-Throttle 7 1 LEVER-Throttle 8 1 LEVER-Throttle 9 1 LINK-Throttle 10 1 ROLLER 11 3 SCREW (#10-32 x.750) 12 3 WASHER 13 3 LOCKWASHER (#10 Externl) 14 1 DECAL-Cution NOVEMBER 1999 Pge 3B-5

6 Fuel Lines A C B D A = TO TOP CARB B = TO MIDDLE CARB C = TO BOTTOM CARB D = TO FUEL PRIMER PUMP Pge 3B NOVEMBER 1999

7 TORQUE REF. NO. QTY. DESCRIPTION l. in. l. ft. N m 1 1 BRACKET-Cold Strt Solenoid 2 1 SOLENOID-Cold Strt 3 1 TUBING (28.00 in. Bulk) (Cut in.) 4 2 CLAMP 5 1 HOSE (2.750 in.) 6 3 CABLE TIE (8.00 in.) 7 3 HOSE (26.00 in. Bulk) (Cut in.) 8 6 NUT ( ) 9 6 STUD (.250 x 1.125) 10 3 GASKET-Cruretor Mount 11 6 LOCKWASHER (.250) 12 6 SCREW ( x.875) 13 6 CLAMP 14 2 HOSE (38.00 in. Bulk) (Cut in.) 15 1 HOSE (9.00 in. Bulk) (Cut 8.00 in.) 16 1 HOSE (9.00 in.) 17 2 CABLE TIE (8.00 in.) 18 1 TUBING (15.00 in. Bulk) (Cut in.) NOVEMBER 1999 Pge 3B-7

8 Cruretor Pge 3B NOVEMBER 1999

9 TORQUE REF. NO. QTY. DESCRIPTION l. in. l. ft. N m 1 CARBURETOR (TOP) (WMV-9-1) 1 1 CARBURETOR (CENTER) (WMV-9-2) 1 CARBURETOR (BOTTOM) (WMV-9-3) 2 6 COVER-Idle Circuit 3 6 GASKET-Idle Circuit Cover 4 12 SCREW-Idle Circuit Cover GASKET-Cruretor Mount 6 2 JET-Idle Air Vent (.050) (TOP & CENTER) (PORT) JET-Idle Air Vent (.054) (BOTTOM) (PORT) JET-Bowl Vent (.080) JET-Idle Air Vent (.050) (STARBOARD) CAP-Limiter 10 6 SCREW & SPRING-Idle Mixture 11 3 LEVER KIT 12 3 SPACER 13 3 SPRING-Throttle Return 14 3 GASKET-Fuel Bowl 15 3 FLOAT ASSEMBLY 16 3 SHAFT-Flot 17 3 SCREW-Flot Pin VALVE SEAT KIT 19 3 GASKET-Vlve Set 20 1 BOWL-Fuel (TOP) 2 BOWL-Fuel (CENTER & BOTTOM) SCREW-Fuel Bowl 22 6 PLUG KIT-Drin GASKET-Drin Plug 24 6 JET-Min Fuel (.076) (PORT & STBD) FITTING-Tee (TOP & CENTER) ELBOW (BOTTOM) NOVEMBER 1999 Pge 3B-9

10 Cruretor Enrichener Hose Fitting 2 -Cruretor Numer 3 -Fuel Mixture Adjustment Screw 4 -Bck Drft Vent Jet 5 -Idle Air Bleed Jet 6 -High Speed Fuel Jet Access Plug (2) 7 -Fuel Line Fitting 8 -Min Nozzle Well Vent (2) Pge 3B NOVEMBER 1999

11 Cruretor Fuel Circuits CARBURETORS Flot Bowl Circuit c Key Air Fuel i j h e f -To Engine Crnkcse -Throttle Plte c -Cruretor Venturi d-flot e -Flot Bowl f -Min Fuel Well g-min Jet h-fuel from Fuel Pump i -Inlet Set j -Inlet Needle Fuel from the fuel pump enters the cruretor through the fuel inlet fitting nd fills the owl until the flot moves the inlet needle ginst the fuel inlet set. With the inlet needle ginst the inlet set, the fuel inside the flot owl is t it s mximum level. Fuel inside the owl flows through the min fuel jet nd fills the min fuel well. g d NOVEMBER 1999 Pge 3B-11

12 Idle Circuit c n m l k f d Key e Air Fuel g h j i -Idle Pssge -Idle Mixture Screw c -Bck Drft Jet d-idle Air Jet e -Therml Air Vlve (open) f -Air Flow g-flot Bowl h-idle Tue i -Min Fuel Jet j -Min Fuel Well k -Secondry Idle Air Bleed l -Throttle Plte m-off-idle Ports n-off-idle Pssge As the engine rottes, the piston moves wy from the crnkcse. This movement cretes low pressure re ehind the throttle plte. Atmospheric pressure pushes ir through the cruretor throt (venturi), pst the throttle plte (smll hole in plte) nd into the low pressure re inside the crnkcse. Atmospheric pressure enters the flot owl chmer through the ck drft jet. This pressure forces fuel towrd the low pressure re ehind the throttle plte. Fuel flows:. Through the min fuel jet into the min fuel well, (1.) Up the idle tue, (2.) Through the off-idle pssges, (3.) Pst the idle mixture screw, (4.) Into the idle pssge (5.) And into the cruretor throt. Air enters the idle circuit through the idle ir jet nd secondry idle ir leed. This ir mixes with the fuel inside the idle pssge efore the sir/fuel mixture is dischrged into the engine. Rotting the idle mixture screw will chnge the ir/fuel mixture t idle speeds. Pge 3B NOVEMBER 1999

13 Cold Strt Circuit CARBURETORS Key Air Fuel Off-Idle Circuit -Therml Air Vlve (closed) -Air Flow A cold engine will require richer mixture. Fuel is supplied to the cruretors y the solenoid operted enrichner vlve. d c f e Key Air Fuel -Off-Idle Ports -Off-Idle Pssge c -Idle Air Jet d-from Open Therml Air Vlve e -Air Flow f -Throttle Plte NOVEMBER 1999 Pge 3B-13

14 Min Circuit As the throttle pltes rotte pst the off-idle ports, the ports re exposed to the low pressure re ehind the throttle plte. Additionl fuel flows through the off-idle pssge; through the rer port; nd s the throttle plte continues to rotte, through the forwrd port. c i h d Key Air Fuel g e f -From Open Therml Air Vlve -Air Flow c -Venturi d-min Dischrge Air Inlet Tue e -Cross Holes f -Min Fuel Well g-min Fuel Jet h-min Dischrge Nozzle i -Throttle Plte As the throttle plte rottes pst the off-idle ports, the low pressure re extends to the min dischrge nozzle. In ddition, the incresed ir flow through the cruretor ore cretes low pressure re inside the venturi. These comined forces crete strong suction over the min dischrge tue. Fuel flows: 1. Through the min fuel jet into the min fuel well, 2. Up the min dischrge nozzle, 3. Into the venturi. Air is mixed with the fuel to mke it lighter, ir enters the min fuel well through the min dischrge ir inlet tue. Cross holes re drilled in the min dischrge tue, llowing the ir to mix with the fuel inside the min well. As the throttle plte continues to open, dditionl fuel is drwn out of the min dischrge tue, exposing dditionl cross holes. At full throttle, the fuel mixture is controlled y the size of the min fuel jet. Pge 3B NOVEMBER 1999

15 Bck Drft Circuit CARBURETORS g f d c Key Air Fuel NOTE: Fuel Flow Not Shown For Clrity -Bck Drft Port -Bck Drft Jet c -Air Flow d-min Dischrge Tue e -Fuel Bowl f -Fuel Bowl Vent Pssge g-throttle Plte At prtil throttle settings, the ck drft circuit lens out the mixture for incresed fuel economy. The ck drft circuit uses the flot owl vent circuit nd owl vent jet to len out the ir/fuel mixture. The owl vent jet limits the mount of ir entering the flot owl vent circuit. With the throttle plte positioned correctly, the low pressure re is exposed to the ck drft port inside the cruretor ore. The flot owl vent circuit is connected y pssges to the ck drft port. The low pressure re pulls ir out of the owl vent circuit. Due to the size of the vent jet nd the ir loss through the ck drft port, the ir pressure on the fuel inside the fuel owl is lowered to elow tmospheric pressure. Lower pressure on the fuel inside the flot owl, lowers the mount of fuel eing forced out of the min dischrge tue. e NOVEMBER 1999 Pge 3B-15

16 Cruretor Specifictions SYNCHRONIZING CARBURETORS IDLE MIXTURE SCREW To synchronize cruretors, refer to Timing/Synchronizing/Adjusting section. For est running qulity, the djustle idle mixture screws re set t the fctory with the limit ts pointing stright up. If djustment is required, ll idle mixture screws must e turned the sme mount nd the sme direction. Turning the idle mixture screws (recommended 1/8 turn t time) clockwise will len the idle mixture. Turning the idle mixture screws counterclockwise will richen the idle mixture. FLOAT LEVEL ADJUSTMENT There is one flot nd one flot owl for 2 cylinders. To set flot height, invert flot owl nd djust flot tng until top of flot is even with top of flot owl. JET LOCATION FOR EACH CYLINDER Cruretor jets nd djustment screw instlled in the strord side of the cruretor supply fuel to the port cylinder, jets nd djustment screw instlled in the port side supply fuel to the strord cylinder. NOTE: The idle jet nd ck drft jet ffect oth cylinders. Pge 3B NOVEMBER 1999

17 Cruretor Plcement nd Jet Loction for Ech Cylinder CARBURETORS TOP WMV 14-1A Cylinder #2 A Cylinder #1 MIDDLE WMV 14-2A Cylinder #4 A Cylinder #3 BOTTOM WMV 14-3A Cylinder #6 A Cylinder #5 A Bckdrft Jet Affects Both Cylinders NOTE: Cruretor jets nd djustment screw instlled in the strord side of the cruretor supply fuel to the port cylinder, jets nd djustment screw instlled in the port side supply fuel to the strord cylinder NOVEMBER 1999 Pge 3B-17

18 Cruretor Jet Plcement Jet Prt Numer Chrt NOTE: Jets listed re for engine opertion from feet (0 1524m) of elevtion. Cruretor Identifiction Numer WMV 14-1A WMV 14-2A WMV 14-3A PORT Bore STBD Bore PORT Bore STBD Bore PORT Bore STBD Bore Min Jet Idle Air Bleed Jet Bck Drft Vent Jet c c PORT CYL. BORE CYLINDERS 2,4,6 (STBD. SIDE of ENGINE) STBD. CYL. BORE CYLINDERS 1,3,5 (PORT SIDE of ENGINE) Pge 3B NOVEMBER 1999

19 Jet Orifice Size (inch) JET ORIFICE SIZE/PART NUMBER CHART CARBURETORS Jet Jet Jet Orifice Orifice Orifice Prt Numer Size Prt Numer Size Prt Numer Size Prt Numer (inch) (inch) (inch) Jet Orifice Size (inch) JET ORIFICE SIZE/PART NUMBER CHART 8-32 Jet Jet Jet Orifice Orifice Orifice Prt Numer Size Prt Numer Size Prt Numer Size Prt Numer (inch) (inch) (inch) NOTE: Thred size for V-6 model cruretor min, idle ir nd ck drft jets re NOTE: Thred size for V-6 model cruretor progression jets re NOVEMBER 1999 Pge 3B-19

20 Removing Cruretor(s) from Engine 1. Remove top cowling. IMPORTANT: Plce n identifying mrk on ech cruretor efore removl s ech cruretor must e reinstlled in sme loction from which removed. NOTE: As ech cruretor is removed from intke mnifold, their respective fuel enrichment hose should e disconnected. 2. Remove ir ox cover nd het shield from engine. 3. Remove throttle linkge from throttle levers s shown. 4. Remove oil pump link rod from throttle lever Throttle Linkge -Oil Pump Link Rod 5. Remove fuel hose nd fuel enrichment vlve hose from cruretors Fuel Hose -Enrichment Vlve Hoses 6. Cruretors my now e removed individully. Mrk loction of ech cruretor nd reinstll in sme loction. Remove cruretor(s) secured y two nuts nd two llen hed type olts. Pge 3B NOVEMBER 1999

21 Throttle Shft Screws CARBURETORS NOTE: It is recommended tht the screws securing the throttle pltes to the throttle shft NOT BE REMOVED due to the difficulty in otining correct lignment of throttle pltes during ressemly. If screws must e removed, pply Loctite 271 to screw threds efore reinstlling screws. c -Throttle Shft -Throttle Shutter Plte c -Screws Flot Adjustment NOTE: Flot height djustment is the only djustment mde to djust flot setting. 1. Adjust flot height y turning fuel owl upside-down, then djust flot t until flot is level with edge of fuel owl. Adjust flot t if necessry. d c -Flot (Adjust y ending t) -Fuel Bowl (Upside-Down) c -Flot Level Even with Bowl Edge d-flot T NOVEMBER 1999 Pge 3B-21

22 Instlling Cruretor(s) to Engine 1. Plce new cruretor gskets onto cruretor mounting studs on intke mnifold. 2. Instll cruretors (in respective loctions) onto mounting studs nd secure in plce with nuts nd llen type olts. 3. Connect enrichment hoses nd fuel hoses. Secure hoses in plce using st-strps Fuel Hose -Enrichment Vlve Hose 4. Attch throttle linkge nd oil pump link rod to cruretors s shown Throttle Linkge -Oil Pump Link Rod 5. Re-synchronize cruretors following cruretor instlltion. Refer to Timing/Synchronizing/Adjusting Section 2C. IMPORTANT: Inspect ll fuel hose connections, nd cruretor flot owl split lines for fuel leks with engine running. Also inspect ech cruretor throt, with outord running t low RPM, for fuel driling out of vent tue which would e indictive of flot nd/or needle nd set ssemly not functioning properly. IMPORTANT: Engine should not e operted ove 3000 RPM with ir ox cover removed s engine will run too len nd internl dmge could result. Pge 3B NOVEMBER 1999