Tle of Contents FUEL SYSTEM Section 3A - Cruretor/Fuel Pump CARBURETOR/FUEL PUMP Specifictions........................... 3A-2 Specil Tools........................... 3A-2 Notes:................................. 3A-3 Cruretor (20/25/JET 20)................ 3A-4 Cruretor (20/25/JET 20)................ 3A-6 Cruretor (Sepro/Mrthon 15/25 & Super 15)............................ 3A-8 Cruretor Adjustments.................. 3A-10 Low Speed Mixture Screw............. 3A-10 Min Jet............................. 3A-10 High Altitude Jet Chrt................ 3A-11 Cruretor Jrt Orifice Size Chrt.......... 3A-12 Cruretor Flot Adjustment........... 3A-13 Cruretor Adjustments............... 3A-14 Electric Choke/Enrichener Adjustment.. 3A-19 Fuel System Trouleshooting............. 3A-20 Generl Informtion.................. 3A-20 Cruretor Removl..................... 3A-23 Cruretor Instlltion................... 3A-24 Fuel Pump............................. 3A-27 Removl nd Disssemly............ 3A-27 Clening nd Inspection............... 3A-27 Ressemly nd Instlltion........... 3A-27 Primer System.......................... 3A-28 Symptoms of Defective Primer System.. 3A-28 Servicing Sight Bowl Fuel Filter........... 3A-29 3 A 90-826883R03 NOVEMBER 2002 Pge 3A-1
Specifictions CARBURETOR SPECIFI- CATIONS Idle RPM (In Forwrd Ger) Wide Open Throttle (WOT) RPM 20 25 Idle Mixture Screw Adjustment (Preset-Turns Out) 20 20 Jet 25/25 Sepro/25 Mrthon Flot Level Min Jet Size (10-32 Thred Size) 1994 1 / 2 through 1996-20 (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) Electric Choke Gp 750 ± 50 4500-5500 5000-6000 1 ± 1/4 Turn 1-1/2 ± 1/2 Turn 1-1/4 ± 1/4 Turn 1.0 in. (25.4 mm) 0.044 in. (1.12 mm) 0.076 in. (1.93 mm) 0.076 in. (1.93 mm) 0.080 in. (2.03 mm) 0.076 in. (1.93 mm) 0.044 in. (1.12 mm) 0.076 in. (1.93 mm) 0.080 in. (2.03 mm) 0.025 in. (0.635 mm) Specil Tools 1. Cruretor Scle Pge 3A-2 90-826883R03 NOVEMBER 2002
Notes: CARBURETOR/FUEL PUMP 90-826883R03 NOVEMBER 2002 Pge 3A-3
Cruretor (20/25/JET 20) 20 19 18 13 21 2 1 28 27 3 12 14 22 11 5 23 25 6 24 10 9 4 7 8 15 26 = CONTENTS OF PRIMER/INJECTOR KIT, PART NO. 1395-9844A1, REFERENCE NO. 26 Pge 3A-4 90-826883R03 NOVEMBER 2002
Cruretor (20/25/JET 20) TORQUE REF. NO. QTY. DESCRIPTION l. in. l. ft. N m 1 CARBURETOR (WMC-52-20HP) 1 1 CARBURETOR (WMC-53-25HP) 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 (.044-20HP) 7 1 JET min fuel (.076-25HP/JET 20) 8 1 PLUG jet retiner 32 3.6 9 1 COVER diphrgm 10 4 SCREW diphrgm cover 14 1.6 11 1 BODY fuel pump 12 5 SCREW fuel pump cover 18 2.0 13 1 COVER fuel pump 14 1 COVER fuel pump (JET 20) 15 1 PLUG 32 3.6 1 GASKET/DIAPHRAGM KIT 1 REPAIR PARTS KIT 18 1 PLATE cover (MANUAL) 19 1 ELECTRIC CHOKE (ELECTRIC) 20 2 SCREW cover plte 18 2.0 21 1 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 90-826883R03 NOVEMBER 2002 Pge 3A-5
Cruretor (20/25/JET 20) * = CONTENTS OF PRIMER/INJECTOR KIT, P/N 1395 9844A1, REFERENCE #25 Pge 3A-6 90-826883R03 NOVEMBER 2002
Cruretor (20/25/JET 20) TORQUE REF. NO. QTY. DESCRIPTION l. in. l. ft. N m 1 1 CARBURETOR (WMC-64-20HP) 1 CARBURETOR (WMC-65-25HP)(JET 20) 1 THROTTLE VALVE (20HP) 2 1 THROTTLE VALVE (25HP/JET 20) 3 1 THROTTLE SHAFT 4 1 SCREW 5 1 SPRING 6 1 VALVE inlet needle 1 JET min fuel (.044-20HP) 7 1 JET min fuel (.076-25HP/JET 20) 8 1 PLUG jet retiner 32 3.6 9 1 COVER diphrgm 10 4 SCREW diphrgm cover 14 1.6 11 1 BODY fuel pump 12 5 SCREW fuel pump cover 18 2.0 13 1 COVER fuel pump 14 1 PLUG 32 3.6 15 1 GASKET/DIAPHRAGM KIT 1 REPAIR PARTS KIT 1 PLATE cover (MANUAL) 18 1 ELECTRIC CHOKE (ELECTRIC) 19 2 SCREW cover plte 18 2.0 20 1 GASKET cruretor 21 1 DIAPHRAGM/GASKET 22 1 GASKET 23 1 FLOAT PIN 24 1 FLOAT LEVER 25 1 PRIMER/INJECTOR SERVICE KIT (See illustrtion for contents) 26 1 FUEL BOWL 27 1 FLOAT 28 1 GASKET 29 1 SCREW 30 1 SCREW 31 1 NUT 90-826883R03 NOVEMBER 2002 Pge 3A-7
Cruretor (Sepro/Mrthon 15/25 & Super 15) 20 18 10 21 2 9 26 1 3 15 6 25 11 23 5 24 12 14 22 4 19 28 27 13 7 8 Pge 3A-8 90-826883R03 NOVEMBER 2002
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 32 3.6 9 1 CHOKE SHAFT 10 1 CHOKE LEVER 11 1 BODY fuel pump 12 5 SCREW fuel pump cover 18 2.0 13 1 COVER pump (WMC-54/54A/56/56A) 14 1 COVER fuel pump (WMC-46/46A) 15 1 CHOKE VALVE 1 GASKET/DIAPHRAGM KIT 1 REPAIR PARTS KIT 18 1 PLATE cover 19 1 SCREW owl drin 14 1.6 20 2 SCREW cover plte 18 2.0 21 1 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 90-826883R03 NOVEMBER 2002 Pge 3A-9
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 25.080 None None 1.0 in. (25.4 mm) WMC - 44 20.044 None None 1.0 in. (25.4 mm) WMC - 52 20.044 None None 1.0 in. (25.4 mm) WMC - 53 WMC - 53A WMC - 54 Commercil 25.076 None None 1.0 in. (25.4 mm) 25.080 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 Low Speed Mixture Screw Rich Len -Low Speed Mixture Screw Min Jet -Min Jet High Altitude High Speed Jetting Altitude 0-5000 ft. (0-1524m) 5000-7500 ft. (1524-2286m) 7500-10000 (2286-3048m) Min Jet 20 25 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-10 90-826883R03 NOVEMBER 2002
High Altitude Jet Chrt Feet Meter Jet Size 1000 304.8 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 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. 2000 609.6 3000 914.4 4000 1219.2 5000 1524 6000 1828.8 7000 2133.6 8000 2438.4 9000 2743.2 10000 3048 1100033 52.8 12000 3657.6 0.034 0.034 0.034 0.032 0.032 0.032 0.032 0.032 0.032 0.030 0.030 0.030 0.030 0.036 0.036 0.036 0.034 0.034 0.034 0.034 0.034 0.032 0.032 0.032 0.032 0.032 0.038 0.038 0.038 0.036 0.036 0.036 0.036 0.036 0.034 0.034 0.034 0.034 0.034 0.040 0.040 0.040 0.038 0.038 0.038 0.038 0.038 0.036 0.036 0.036 0.036 0.034 0.042 0.042 0.042 0.040 0.040 0.040 0.040 0.038 0.038 0.038 0.038 0.038 0.036 0.044 0.044 0.044 0.042 0.042 0.042 0.042 0.040 0.040 0.040 0.040 0.038 0.038 0.046 0.046 0.046 0.044 0.044 0.044 0.044 0.042 0.042 0.042 0.042 0.040 0.040 0.048 0.048 0.048 0.046 0.046 0.046 0.046 0.044 0.044 0.044 0.042 0.042 0.042 0.050 0.050 0.050 0.048 0.048 0.048 0.046 0.046 0.046 0.046 0.044 0.044 0.044 0.052 0.052 0.050 0.050 0.050 0.050 0.048 0.048 0.048 0.048 0.046 0.046 0.046 0.054 0.054 0.052 0.052 0.052 0.052 0.050 0.050 0.050 0.048 0.048 0.048 0.048 0.056 0.056 0.054 0.054 0.054 0.054 0.052 0.052 0.052 0.050 0.050 0.050 0.048 0.058 0.058 0.056 0.056 0.056 0.056 0.054 0.054 0.054 0.052 0.052 0.052 0.050 0.060 0.060 0.058 0.058 0.058 0.056 0.056 0.056 0.054 0.054 0.054 0.052 0.052 0.062 0.062 0.060 0.060 0.060 0.058 0.058 0.058 0.056 0.056 0.056 0.054 0.054 0.064 0.064 0.062 0.062 0.062 0.060 0.060 0.060 0.058 0.058 0.058 0.056 0.056 0.066 0.066 0.064 0.064 0.064 0.062 0.062 0.062 0.060 0.060 0.060 0.058 0.058 0.068 0.068 0.066 0.066 0.066 0.064 0.064 0.064 0.062 0.062 0.060 0.060 0.060 0.070 0.070 0.068 0.068 0.068 0.066 0.066 0.064 0.064 0.064 0.062 0.062 0.062 0.072 0.072 0.070 0.070 0.070 0.068 0.068 0.066 0.066 0.066 0.064 0.064 0.062 0.074 0.074 0.072 0.072 0.070 0.070 0.070 0.068 0.068 0.068 0.066 0.066 0.064 0.076 0.076 0.074 0.074 0.072 0.072 0.072 0.070 0.070 0.068 0.068 0.068 0.066 0.078 0.078 0.076 0.076 0.074 0.074 0.074 0.072 0.072 0.070 0.070 0.068 0.068 0.080 0.080 0.078 0.078 0.076 0.076 0.076 0.074 0.074 0.072 0.072 0.070 0.070 0.082 0.082 0.080 0.080 0.078 0.078 0.076 0.076 0.076 0.074 0.074 0.072 0.072 0.084 0.084 0.082 0.082 0.080 0.080 0.078 0.078 0.076 0.076 0.076 0.074 0.074 0.086 0.086 0.084 0.084 0.082 0.082 0.080 0.080 0.078 0.078 0.076 0.076 0.074 0.088 0.088 0.086 0.086 0.084 0.084 0.082 0.082 0.080 0.080 0.078 0.078 0.076 0.090 0.090 0.088 0.088 0.086 0.086 0.084 0.084 0.082 0.082 0.080 0.080 0.078 0.092 0.092 0.090 0.090 0.088 0.088 0.086 0.086 0.084 0.084 0.082 0.082 0.080 0.094 0.094 0.092 0.092 0.090 0.090 0.088 0.088 0.086 0.086 0.084 0.084 0.082 0.096 0.096 0.094 0.094 0.092 0.092 0.090 0.090 0.088 0.086 0.086 0.084 0.084 0.098 0.098 0.096 0.096 0.094 0.092 0.092 0.090 0.090 0.088 0.088 0.086 0.086 90-826883R03 NOVEMBER 2002 Pge 3A-11
Cruretor Jet Orifice Size Chrt Jet Orifice Size - Inches Prt Numer 0.034 19266034 0.036 19266036 0.038 19266038 0.040 19266040 0.042 1399-5315 0.044 1395-7394 0.046 1399-53 0.048 1395-6246 0.050 1395-6028 0.052 1395-6359 0.054 1399-5225 0.056 1399-5213 0.058 1395-7831 0.060 1395-6487 0.062 1399-42 0.064 1399-42 0.066 1399-4215 0.068 1395-6029 0.070 1395-6030 0.072 1395-6207 0.074 1399-3794 0.076 1399-3796 0.078 1395-6680 0.080 1395-6201 0.082 1399-3518 0.084 1399-35 0.086 1395-5815 0.088 1395-6202 0.090 1395-6247 0.092 1395-5733 0.094 1395-8423 0.096 1399-6249 0.098 1395-7335 NOTE: 32 Thred Size Pge 3A-12 90-826883R03 NOVEMBER 2002
Cruretor Flot Adjustment CARBURETOR/FUEL PUMP 1 in. (25.4 mm) -Cruretor Scle (91-36392) -Mesured from Bottom of Flot 111 c d -Flot -Flot Hinge c -Flot Pin d-bend Flot Arm Here to Adjust Flot Level e -Needle e 52646 90-826883R03 NOVEMBER 2002 Pge 3A-13
Cruretor Adjustments 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 57049 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. 57037 Pge 3A-14 90-826883R03 NOVEMBER 2002
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 57070 90-826883R03 NOVEMBER 2002 Pge 3A-15
LOW SPEED MIXTURE SCREW 1. Remove ccess plug from cruretor ir intke cover (models so equipped). -Access Plug -Intke Cover 57072 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 57071 Pge 3A- 90-826883R03 NOVEMBER 2002
IDLE WIRE ADJUSTMENT 1. Push primer/fst idle kno completely in nd rotte fully counterclockwise. 2. Shift engine to Neutrl. 3. Adjust screw to remove ll clernce etween idle wire nd trigger. 57037 -Screw -Idle Wire 57070 4. Check fst idle speed y turning primer kno to full clockwise position. Fst idle speed should e 1500-2000 RPM. 90-826883R03 NOVEMBER 2002 Pge 3A-
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. 57037 3. 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 57071 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. Pge 3A-18 90-826883R03 NOVEMBER 2002
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 57070 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. Electric Choke/Enrichener Adjustment (Models Equipped) 1. With the engine off, check the gp etween the electric choke plunger nd cruretor. 2. Adjust the electric choke y loosening cover plte screws nd moving cover plte to otin 0.025 in. (0.635 mm) gp. Torque screws to 18 l-in. (2 Nm) nd recheck gp. 3. Plunger must cover hole (in cruretor) when choked. -Gp = 0.025 in. (0.635 mm) -Cover Plte Screw 00228 90-826883R03 NOVEMBER 2002 Pge 3A-19
Fuel System Trouleshooting 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 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. 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. Corrective Action Review strting procedure s outlined in Opertion nd Mintennce Mnul. 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. Pge 3A-20 90-826883R03 NOVEMBER 2002
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. 90-826883R03 NOVEMBER 2002 Pge 3A-21
Prolem: Engine Floods Possile Cuse Dirt or deris re preventing inlet needle from seting. Worn inlet needle. Punctured flot Incorrect flot setting 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 Flush out inlet set nd clen inlet needle. Replce Replce. Reset flot. 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 filters 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. Pge 3A-22 90-826883R03 NOVEMBER 2002
Cruretor Removl NOTE: Air intke cover hs een removed for visul clrity. 1. Loosen primer cm retining screw. 2. Remove retining clip. CARBURETOR/FUEL PUMP -Screw -Retining Clip 57069 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 57068 90-826883R03 NOVEMBER 2002 Pge 3A-23
Cruretor Instlltion 1. Instll cruretor with new gsket onto mounting studs. Strt ttching nuts ut do not tighten. -Gsket -Nuts 57067 2. Instll primer ssemly onto cruretor. Position lignment hole on ssemly over post on ottom of cruretor. -Alignment Hole -Post 57066 Pge 3A-24 90-826883R03 NOVEMBER 2002
3. Instll ir cover onto cruretor nd secure with 2 screws. 4. Tighten cruretor ttching nuts. CARBURETOR/FUEL PUMP -Screws -Nuts 57075 5. Secure fuel line to cruretor with st-strp. 6. Reconnect link wire to fst idle lever. c -Fuel Line -St-Strp c -Link Wire 57070 90-826883R03 NOVEMBER 2002 Pge 3A-25
7. Push down on primer rm nd insert primer kno, ezel nd slide lock into primer ssemly. c d 57068 -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 57069 Pge 3A-26 90-826883R03 NOVEMBER 2002
Fuel Pump CARBURETOR/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 f 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 90-826883R03 NOVEMBER 2002 Pge 3A-27
Primer System 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 e f g 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 Pge 3A-28 90-826883R03 NOVEMBER 2002
Servicing Sight Bowl Fuel Filter CARBURETOR/FUEL PUMP 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 twist fuel filter ssemly when removing or instlling. PULL STRAIGHT DOWN when removing ssemly. PUSH STRAIGHT UP when instlling ssemly. Turning or twisting 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. 1 -Fuel Line 2 -St-strp (4) 3 -Cover 4 -Filter 5 -Ruer Seling Wsher 6 -Sight Bowl 7 -Fuel Line Connector 90-826883R03 NOVEMBER 2002 Pge 3A-29