FUEL SYSTEM. Section 3A - Carburetor/Fuel Pump

Transcription

1 Tle of Contents FUEL SYSTEM Section 3A - Cruretor/Fuel Pump CARBURETOR/FUEL PUMP Specifictions A-1 Specil Tools A-1 Cruretor (20/25/JET 20) A-2 Cruretor (Sepro/Mrthon 15/25 & Super 15). 3A-4 Cruretor Adjustments A-6 Low Speed Mixture Screw A-6 Min Jet A-6 High Altitude Jet Chrt A-7 Cruretor Flot Adjustment A-8 Cruretor Adjustments A-9 Fuel System Trouleshooting A-15 Generl Informtion A-15 Specifictions Cruretor Removl A-18 Cruretor Instlltion A-19 Fuel Pump A-22 Removl nd Disssemly A-22 Clening nd Inspection A-22 Ressemly nd Instlltion A-22 Primer System A-23 Symptoms of defective primer system A-23 Servicing Sight Bowl Fuel Filter A-24 3 A CARBURETOR SPECIFI- CATIONS Idle RPM (In Forwrd Ger) Wide Open Throttle (WOT) RPM Idle Mixture Screw Adjustment (Preset-Turns Out) Jet 25/25 Sepro/25 Mrthon Flot Level Min Jet Size / 2 thru (WMC-44) -25/20 Jet (WMC-45) -25 Sepro/Mrthon (WMC-46) -25 Sepro/Mrthon (WMC-46A) 1997 nd Newer -20 Jet (WMC-45) -20 (WMC-52) -25 (WMC-53) -25 Sepro/Mrthon (WMC-54) 750 ± ± 1/4 Turn 1-1/2 ± 1/2 Turn 1-1/4 ± 1/4 Turn 1.0 in. (25.4 mm) in. (1.12 mm) in. (1.93 mm) in. (1.93 mm) in. (2.03 mm) in. (1.93 mm) in. (1.12 mm) in. (1.93 mm) in. (2.03 mm) Specil Tools 1. Cruretor Scle R2 JUNE 1998 Pge 3A-1

2 Cruretor (20/25/JET 20) = CONTENTS OF PRIMER/INJECTOR KIT, PART NO A1, REFERENCE NO. 26 Pge 3A R2 JUNE 1998

3 Cruretor (20/25/JET 20) TORQUE REF. NO. QTY. DESCRIPTION l. in. l. ft. N m 1 CARBURETOR (WMC-52-20HP) 1 CARBURETOR (WMC-53-25HP) 1 1 CARBURETOR (WMC-44-20HP) 1 CARBURETOR (WMC-45-25HP)(JET 20) 1 THROTTLE VALVE (20HP) 2 1 THROTTLE VALVE (25HP/JET 20) 1 THROTTLE SHAFT (20-WMC-44) 3 1 THROTTLE SHAFT (25-WMC-45)(JET 20) THROTTLE SHAFT(20/25HP)(WMC52/52A/53/53A) 4 1 FUEL BOWL 5 1 FLOAT 6 1 VALVE inlet needle 1 JET min fuel ( HP) 7 1 JET min fuel ( HP/JET 20) 8 1 PLUG jet retiner COVER diphrgm 10 4 SCREW diphrgm cover BODY fuel pump 12 5 SCREW fuel pump cover COVER fuel pump 14 1 COVER fuel pump (JET 20) 15 1 PLUG GASKET/DIAPHRAGM KIT 1 REPAIR PARTS KIT 18 1 PLATE cover (MANUAL) 19 1 ELECTRIC CHOKE (ELECTRIC) 20 2 SCREW cover plte GASKET cruretor 22 1 DIAPHRAGM/GASKET 23 1 GASKET 24 1 FLOAT PIN 25 1 FLOAT LEVER 26 1 PRIMER/INJECTOR SERVICE KIT (See illustrtion for contents) 27 1 SCREW 28 1 NUT R2 JUNE 1998 Pge 3A-3

4 Cruretor (Sepro/Mrthon 15/25 & Super 15) Pge 3A R2 JUNE 1998

5 Cruretor (Sepro/Mrthon 15/25 & Super 15) TORQUE REF. NO. QTY. DESCRIPTION l. in. l. ft. N m 1 CARBURETOR (WMC-54) 1 1 CARBURETOR (WMC-46A) 1 CARBURETOR (WMC-56) 1 THROTTLE VALVE (WMC 46/46A/54/54A) 2 1 THROTTLE VALVE (WMC-56/56A) 3 1 THROTTLE SHAFT 4 1 FUEL BOWL 5 1 FLOAT 6 1 VALVE inlet needle 1 JET min fuel (.076) (WMC 46) 7 1 JET min fuel (.080) (WMC 46A/54/54A) 1 JET min fuel (.046) (WMC 56/56A) 8 1 PLUG jet retiner CHOKE SHAFT 10 1 CHOKE LEVER 11 1 BODY fuel pump 12 5 SCREW fuel pump cover COVER pump (WMC-54/54A/56/56A) 14 1 COVER fuel pump (WMC-46/46A) 15 1 CHOKE VALVE 16 1 GASKET/DIAPHRAGM KIT 1 REPAIR PARTS KIT 18 1 PLATE cover 19 1 SCREW owl drin SCREW cover plte GASKET cruretor 22 1 DIAPHRAGM/GASKET 23 1 GASKET 24 1 FLOAT PIN 25 1 FLOAT LEVER 26 1 CHOKE LINK 27 1 SCREW 28 1 NUT R2 JUNE 1998 Pge 3A-5

6 Cruretor Adjustments Cruretor Numer Stmped t Top of Cruretor Mounting Flnge Cruretor Numer WMC - 43 Commercil Model H.P. Min Jet Size Bowl Vent Jet Bck Drg Jet Flot Setting None None 1.0 in. (25.4 mm) WMC None None 1.0 in. (25.4 mm) WMC None None 1.0 in. (25.4 mm) WMC - 53 WMC - 53A WMC - 54 Commercil Low Speed Mixture Screw None None 1.0 in. (25.4 mm) None None 1.0 in. (25.4 mm) Pre-Set Idle Mixture Screw (Open) 1-1/2 Turns 1-1/2 Turns 1-1/2 Turns 1-1/2 Turns 1-1/2 Turns Rich Len Min Jet -Low Speed Mixture Screw -Min Jet Altitude ft. (0-1524m) ft. ( m) ( m) High Altitude High Speed Jetting Min Jet SePro/Mrthon.044 in.*.076 in.*.080 in.*.042 in..074 in..078 in..040 in..072 in..076 in. *Stndrd Min Jet Pge 3A R2 JUNE 1998

7 High Altitude Jet Chrt Feet Meter Jet Size CARBURETOR/FUEL PUMP Fctory instlled min fuel jets re normlly dequte for proper performnce up to pproximtely 5000 feet (1524m) ove se level. Between 2000 feet (609.6m) nd 5000 feet (1524m) the reduction of the min fuel jet(s) my result in improved performnce nd fuel economy. Aove 5000 feet, however, it is recommended tht min jet size e reduced s shown per 1000 feet (304.8m) in the following chrt. RETURN TO LOWER ELEVA- TION: Cruretor jet chnges must e reversed to void len fuel condition when used t low elevtion R2 JUNE 1998 Pge 3A-7

8 Cruretor Flot Adjustment 1 in. (25.4 mm) -Cruretor Scle ( ) -Mesured from ottom of flot 111 c d -Flot -Flot Hinge c -Flot Pin d-bend Flot Arm Here to Adjust Flot Level e -Needle e Pge 3A R2 JUNE 1998

9 Cruretor Adjustments CARBURETOR/FUEL PUMP 1. Plce outord in wter. 2. Check tiller hndle cle djustment for full throttle movement in oth Forwrd nd Reverse gers. Adjust jm nuts for proper trvel nd to eliminte ny slck. -Jm Nuts INITIAL CARBURETOR ADJUSTMENTS Idle Speed Screw (Models So Equipped) 1. Shift outord to Neutrl nd plce throttle twist grip to Slow. 2. Push primer/fst idle kno completely in nd rotte kno fully counterclockwise R2 JUNE 1998 Pge 3A-9

10 3. Bck idle speed screw off of cm follower. 4. Turn idle speed screw inwrd (clockwise) until it just touches cm follower, then inwrd n dditionl 1/2 turn to slightly open throttle plte. -Idle Speed Screw -Cm Follower Pge 3A R2 JUNE 1998

11 LOW SPEED MIXTURE SCREW 1. Remove ccess plug from cruretor ir intke cover (models so equipped) Access Plug -Intke Cover 2. Turn low speed mixture screw slowly inwrd (clockwise) until it sets lightly, then ck screw out (counterclockwise) 1 1/2 to 1 3/8 turns(turning mixture screw in tight will dmge needle nd set). 3. Do not instll ccess plug t this time. -Low Speed Mixture Screw R2 JUNE 1998 Pge 3A-11

12 IDLE WIRE ADJUSTMENT 1. Push primer/fst idle kno completely in nd rotte fully counterclockwise. 2. Shift engine to Neutrl Adjust screw () to remove ll clernce etween idle wire () nd trigger Screw -Idle Wire 4. Check fst idle speed y turning primer kno to full clockwise position. Fst idle speed should e RPM. Pge 3A R2 JUNE 1998

13 IDLE ADJUSTMENT Low speed Mixture Adjustment 1. Strt engine nd llow to wrm up (run for severl minutes). Throttle engine ck to idle for out one minute to llow RPM to stilize. 2. Push primer/fst idle kno completely in nd rotte kno fully counterclockwise With engine running t idling speed while in Forwrd ger, turn low speed mixture screw counterclockwise until engine strts to lod up or fire unevenly from over rich mixture. 4. Slowly turn low speed mixture screw clockwise until cylinders fire evenly nd engine picks up speed Low Speed Mixture Screw 5. Continue turning mixture screw clockwise until too len mixture is otined nd engine slows down nd misfires. 6. Set low speed mixture screw hlfwy etween rich nd len. 7. DO NOT djust lener thn necessry to ttin resonly smooth idling. When in dout, set mixture slightly richer rther thn too len. 8. Check for freedom from 4 cycling etween idle nd 2000 RPM (in Forwrd ger). 9. Instll ccess plug into opening in cruretor ir intke cover R2 JUNE 1998 Pge 3A-13

14 IDLE SPEED ADJUSTMENT (MODELS EQUIPPED WITH IDLE SCREW) 1. With engine running t idle in Forwrd ger, mke sure primer/fst idle kno is pushed completely in nd rotte fully counterclockwise to stop. 2. Adjust idle speed screw () to otin recommended idle speed (see specifictions). -Idle Speed Screw IDLE SPEED ADJUSTMENT (MODELS NOT EQUIPPED WITH AN IDLE SPEED SCREW) For models not equipped with n idle speed screw, the cruretor hs een clirted t the fctory to mintin n idle speed of 650 ± 75 RPM in Forwrd ger. Pge 3A R2 JUNE 1998

15 Fuel System Trouleshooting CARBURETOR/FUEL PUMP Generl Informtion Prolems tht re thought to e cused y the fuel system my, in relity, e 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. Propeller 2. Sprk Plugs 3. Ignition Timing 4. Ignition Sprk Voltge 5. Cylinder Compression 6. Reed Vlves Typicl symptoms nd solutions in trouleshooting fuel system re shown elow: Prolem: Engine Turns Over ut Will Not Strt or Strts Hrd When Cold Prolem: Engine Idles Rough nd Stlls. Prolem: Engine Runs Uneven or Surges. Prolem: Engine Will Not Accelerte. Possile Cuse Corrective Action Improper strting procedure used. Review strting procedure s outlined in Opertion nd Mintennce Mnul. Fuel tnk empty or too low. Improperly mixed fuel. Contminnts (wter,dirt, etc.) in fuel. Fuel tnk ir vent closed or restricted. Pinched, cut, restricted fuel line or loose fuel line connection. Dirty or restricted fuel filter. Choke solenoid or enrichment vlve not operting. Needle nd set in cruretor tht is either stuck open (flooding) or closed (no fuel). Improper cruretor jet, restricted jet or idle mixture screw out of djustment. Improper flot level. Low fuel pump pressure. Defective nti-siphon vlve. Check fuel in 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. Inspect ll fuel lines nd replce s needed. Tighten fuel line connections. Inspect nd replce or clen ll fuel filters. Inspect solenoid or vlve nd wiring. Replce s required. Refer to cruretor disssemly in this section. Refer to cruretor djustments in this section. Refer to cruretor djustments in this section. Disssemle nd inspect fuel pump components. Inspect vlve nd/or test engine without vlve in fuel system R2 JUNE 1998 Pge 3A-15

16 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. Dirty or restricted fuel filter. Low fuel pump pressure. Defective nti-siphon vlve. Needle nd set in cruretor tht is either stuck open or closed. Improper cruretor jet, restricted jet or idle mixture screw out of djustment. Improper flot level. Cruretor loose on intke mnifold. Reed lock loose or gsket defective. Improperly routed or restricted leed hose(s). Dmged fuel pump diphrgm. Cruretor mixing chmer cover leking ir. Off idle holes plugged. Min nozzle or idle nozzle ir leed holes plugged. Dmged reeds. Fuel pick-up outlet tue in fuel tnk crcked. Wrong sprk plug or improper sprk plug gp Improper sprk timing. Corrective Action Check fuel in tnk nd replce if necessry. Check ir vent on tnk. Vent must e open ll-thewy nd free from ny contminnts. Inspect ll fuel lines nd replce s needed. Inspect nd tighten ll fuel line connections. Inspect nd replce or clen ll fuel filters. Disssemle nd inspect fuel pump components. Inspect vlve nd/or test engine without vlve in fuel system. Refer to cruretor djustments in this section. Refer to cruretor djustments in this section. Refer to cruretor djustments in this section. Check tightness of cruretor nuts. Using pressure oil cn, pply 2-cycle oil round reed lock housing/crnkcse housing mtching surfces nd cruretor se. If engine RPM chnges, tighten olts/nuts or replce gskets s required. Refer to leed hose routing in Powerhed section. Disssemle nd inspect fuel pump components. Tighten screws or replce gsket. Blow with compressed ir. Blow with compressed ir. Refer to Section 4 for reed inspection. Replce Instll correct plug or redjust gp. Reset timing to correct specifictions. Pge 3A R2 JUNE 1998

17 Prolem: Engine Floods Possile Cuse Dirt or deris re preventing inlet needle from seting. Worn inlet needle. Punctured flot Incorrect flot setting Corrective Action Flush out inlet set nd clen inlet needle. Replce Replce. Reset flot. Prolem: Engine Runs Too Rich Possile Cuse Fuel level too high. Cruretor floods. Idle nozzle ir holes plugged. Restricted ir flow. Min fuel jet loose. Corrective Action Reset flot to correct level. See preceding Engine Floods. Blow out with compressed ir. Inspect cowl ir inlet nd cruretor for ostructions. Retighten jet. Prolem: Fuel Blowck Out of Cruretor Prolem: Unle to Reduce Engine RPM to Slow Idle Possile Cuse Corrective Action Chipped or roken reeds on reed lock. Replce reeds. Prolem: Rough Idle Possile Cuse Corrective Action Excessive prelod on reeds. Replce reeds. Prolem: Engine Runs Too Len Possile Cuse Cruretor is loose. Air leks pst mixing chmer cover. Fuel level is too low. Clogged high speed jet. Restricted fuel flow to cruretor. Incorrect high speed jet. Idle mixture set too len. Air lekge into fuel system. Anti-siphon vlve restricting fuel flow. Corrective Action Tighten olts securely. Tighten cover or replce gsket. Reset flot level. Inspect jet for vrnish or deris nd clen. Check fuel lines nd filter(s) for restricted flow. Refer to min jet chrt nd replce with proper jet. Adjust to run richer (turn idle mix screw counterclockwise). Inspect fuel line connections, hose clmps, fuel pump nd fuel outlet tue (locted in fuel tnk) for loose fittings. Inspect vlve nd/or test engine without vlve in fuel system R2 JUNE 1998 Pge 3A-

18 Cruretor Removl NOTE: Air intke cover hs een removed for visul clrity. 1. Loosen primer cm retining screw. 2. Remove retining clip Screw -Retining Clip 3. Push down on primer rm nd pull primer kno, ezel nd slide lock out of ottom cowl. 4. Remove link wire from fst idle lever. 5. Disconnect fuel line from cruretor. 6. Remove cruretor mounting nuts. 7. Lift cruretor from engine. e c d -Primer Arm -Primer Kno c -Bezel d-slide Block e -Link Wire Pge 3A R2 JUNE 1998

19 Cruretor Instlltion CARBURETOR/FUEL PUMP 1. Instll cruretor with new gsket onto mounting studs. Strt ttching nuts ut do not tighten Gsket -Nuts 2. Instll primer ssemly onto cruretor. Position lignment hole on ssemly over post on ottom of cruretor. -Alignment Hole -Post R2 JUNE 1998 Pge 3A-19

20 3. Instll ir cover onto cruretor nd secure with 2 screws. 4. Tighten cruretor ttching nuts. -Screws -Nuts 5. Secure fuel line to cr with st-strp. 6. Reconnect link wire to fst idle lever c -Fuel Line -St-strp c -Link Wire Pge 3A R2 JUNE 1998

21 7. Push down on primer rm nd insert primer kno, ezel nd slide lock into primer ssemly. c d Primer Arm -Primer Kno c -Bezel d-slide Block 8. Tighten screw to secure slide lock in plce. 9. Align notch in ck side of ezel with t on ottom cowl nd secure ezel in plce with retining clip. -Screw -Retining Clip R2 JUNE 1998 Pge 3A-21

22 Fuel Pump Removl nd Disssemly Clening nd Inspection IMPORTANT: Fuel pump check vlve diphrgm nd gsket should NOT e re-used once the fuel pump is disssemled. 1. Remove 5 screws securing fuel pump ssemly to cruretor. 2. Seprte fuel pump components. 1. Clen nd dry ll prts thoroughly. 2. Inspect pump ody nd se on cruretor for nicks, crcks or rough gsket surfce. 3. Inspect pump check vlve diphrgm. Diphrgm MUST BE flt nd free from holes nd imperfections. 4. Pump ody surfce elow check vlves MUST BE flt so tht check vlve will set. Ressemly nd Instlltion 1. Inspect ll prts for serviceility. 2. Ressemle fuel pump. 3. Secure fuel pump ssemly to cruretor with 5 screws. Torque screws to 18 l. in. (3.2 N m). k j e c d i h g -Gsket -Pump Body c -Spring d-cp e -Gsket f -Diphrgm g-pump Cover h-lock Wsher (5) i -Screw (5) [Torque screws to 18 l. in. (3.2 N m)] j -Idle Timing Screw k -Nut f Pge 3A R2 JUNE 1998

23 Primer System CARBURETOR/FUEL PUMP The primer system provides extr fuel to the outord whenever the primer kno is pulled out. The primer system components should e inspected crefully for serviceility. The diphrgm nd gskets should e inspected for cuts or rsions. Replce ccordingly. The primer check ll nd springs should e inspected for deris or vrnish which restrict free movement. SYMPTOMS OF A DEFECTIVE PRIMER SYSTEM 1. Outord is hrd to strt.. Diphrgm is cut.. Primer check ll is stuck in the closed position. c. Primer pssge is plugged with deris or vrnish. 2. Outord smokes excessively t idle.. Primer check ll is not seted due to deris, vrnish or dmged check ll spring. c d f e h i j k -Sel -Screw (4) [Torque to 14 l. in. (1.6 N m)] c -Cover d-diphrgm e -Gsket f -Spring g-primer Bowl h-check Bll i -Spring j -Gsket k -Plug g R2 JUNE 1998 Pge 3A-23

24 Servicing Sight Bowl Fuel Filter WARNING Exercise extreme cution when clening fuel filter elements. Gsoline is extremely flmmle nd highly explosive under certin conditions. Alwys stop the engine nd DO NOT smoke or llow open flmes in the re while clening fuel filter elements. CAUTION DO NOT turn or cock fuel filter ssemly when removing or instlling. PULL STRAIGHT DOWN when removing ssemly. PUSH STRAIGHT UP when instlling ssemly. Turning or cocking fuel filter my rek fuel line connection on filter. The sight owl fuel filter removes dirt nd wter from the fuel. Check the sight owl frequently nd clen the filter s required. 1. Verify tht the sight owl ruer seling ring is properly positioned in the owl. 2. Reinstll element in filter cover. 3. Thred sight owl onto filter cover. 4. Tighten owl securely y hnd Fuel Line 2 -St-strp (4) 3 -Cover 4 -Filter 5 -Ruer Seling Wsher 6 -Sight Bowl 7 -Fuel Line Connector Pge 3A R2 JUNE 1998