briggs & stratton carburetion troubleshooting & repair procedures 1996_carb_trouble_shooting

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As much as we would all like to have a short, simple and effective way of troubleshooting engine problems, there is no short cut to accurate and effective troubleshooting. There is no magic bullet, no teaching method that will change the learning curve drastically. Effective and efficient troubleshooting results from a combination of a thorough understanding of theory, logical as well as accurate testing procedures and experience. The purpose of this session is to provide the technician with the necessary information and procedures to effectively diagnose and repair carburetion system problems correctly and efficiently the first time. Listed below are the three areas this section of your notebook will cover in detail. Most carburetor system problems fall into three distinct categories: S Starting Problems S Performance Problems S Leakage There are times when a carburetor may exemplify all three of the problem categories at the same time. This can be confusing. The information, tests and procedures that follow can be used when a singular problem occurs or when multiple problems are evident. Understanding carburetor theory of operation, following the tests and procedures carefully as well as collecting accurate symptom information will provide you with all of the tools needed to effect an accurate and efficient repair. If you wish to learn more about carburetor theory or troubleshooting, contact your regional Central Sales and Service Distributor or the Customer Education Department at Briggs & Stratton. In order to isolate the various systems for troubleshooting (ignition, compression and carburetion) this text assumes that the recommended ignition system test (using a #19368 spark tester), and a cylinder leakdown test (using a #19413 leakdown tester) have been performed and the technician has no data indicating that these systems could be defective in any way. TROUBLESHOOTING CARBURETION SYSTEMS Carburetion Troubleshooting & Repair Procedures 12 1996 Technical Update Seminar For Briggs & Stratton Discount Parts Call 606-678-9623 or 606-561-4983 www.mymowerparts.com

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Page 1: BRIGGS & STRATTON Carburetion Troubleshooting & Repair Procedures 1996_Carb_Trouble_Shooting

As much as we would all like to have a short, simple and effective way of troubleshooting engine problems,there is no short cut to accurate and effective troubleshooting. There is no magic bullet, no teaching methodthat will change the learning curve drastically. Effective and efficient troubleshooting results from acombination of a thorough understanding of theory, logical as well as accurate testing procedures andexperience.

The purpose of this session is to provide the technician with the necessary information and procedures toeffectively diagnose and repair carburetion system problems correctly and efficiently the first time. Listedbelow are the three areas this section of your notebook will cover in detail.

Most carburetor system problems fall into three distinct categories:

� Starting Problems

� Performance Problems

� Leakage

There are times when a carburetor may exemplify all three of the problem categories at the same time. Thiscan be confusing. The information, tests and procedures that follow can be used when a singular problemoccurs or when multiple problems are evident. Understanding carburetor theory of operation, following thetests and procedures carefully as well as collecting accurate symptom information will provide you with all ofthe tools needed to effect an accurate and efficient repair.

If you wish to learn more about carburetor theory or troubleshooting, contact your regional Central Salesand Service Distributor or the Customer Education Department at Briggs & Stratton.

In order to isolate the various systems for troubleshooting (ignition, compression and carburetion) this textassumes that the recommended ignition system test (using a #19368 spark tester), and a cylinder leakdowntest (using a #19413 leakdown tester) have been performed and the technician has no data indicating thatthese systems could be defective in any way.

TROUBLESHOOTING CARBURETION SYSTEMS

Carburetion Troubleshooting & Repair Procedures

12 1996 Technical Update Seminar

For Briggs & Stratton Discount Parts Call 606-678-9623 or 606-561-4983

www.mymowerparts.com

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TROUBLESHOOTING CARBURETION SYSTEMSStarting Problems

CHOKE OPERATIONAs simple as it sounds, there are a significantnumber of starting problems that could be solved bya proper choke adjustment process. The “GoldenRule” of the systematic troubleshooting process is“Do the easiest thing first.”

The customer complaint of “Hard starting” or “Hardto start cold, starts fine warm” will lead the seasonedtechnician immediately to a complete check of thechoking system, cables and linkage. Too often thecarburetor is removed, cleaned and re-installed onlyto find the problem was a cable out of adjustment.

PRIMERSSome engine models use a primer bulb system toforce fuel up through the main nozzle and into theventuri. This adds additional fuel to start the engine.

To verify that the primer is indeed working, removethe air cleaner assembly and look directly into thethroat of the carburetor. A pulse of fuel should beseen when the primer is depressed. The amount offuel coming out of the nozzle is directly related tohow hard and often the primer bulb is depressed.

FUEL SUPPLYA simple check of fuel supply and delivery to thecarburetor is accomplished by mechanically clamp-ing off the fuel line in order to stop fuel flow, thenremoving the line from the inlet fitting of thecarburetor. See Figure 2.

With the fuel cap installed, release the clamp, andallow the fuel to run into a container approved forgasoline. The fuel flow should be as wide as theinside diameter of the line.

If the engine is equipped with a fuel pump, removethe spark plug high tension lead(s) (attach the leadsto a good engine ground) and perform the samestyle test. The fuel should be delivered with distinctpulses at cranking speeds.

Fig. 1

Fig. 2

Fig. 3

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TROUBLESHOOTING CARBURETION SYSTEMSStarting Problems (cont.)

DEBRISAny debris lodged in the main jet of a carburetor cancause an engine to appear under-choked. In somecases (even on primer systems) the debris in the jetcan completely stop any fuel from flowing into thethroat of the carburetor.

The lesson here is that there are multiple factors thatcan affect startability. The faulty operation of thechoke is common but not the singular answer for all“hard to start cold” situations.

ANTI-AFTERFIRE SOLENOIDSBegin troubleshooting the solenoid by checking forbattery voltage at the spade connector (with the keyswitch in the “start” as well as the “run” position). Thenext check is to listen at the bowl of the carburetorfor a distinct click when the ignition switch is turnedto the on position. If a distinct click is not heard,remove the solenoid for further testing.

To test the solenoid itself, attach one pole of a 9 volttransistor radio battery to the spade terminal and theother pole to the solenoid case or black ground wireif so equipped. A sharp distinct movement of theplunger should be seen.

A poor solenoid ground connection or dirty/stale fuelare common causes of anti-afterfire solenoidproblems.

STARTABILITY TESTSThere are two simple ways of confirming that thechoke or primer system is delivering fuel to thecombustion chamber. As stated previously underPRIMERS, remove the air cleaner and visuallyinspect the gasoline stream created in the throat ofthe carburetor when the primer bulb is depressed.

On a choke type carburetor, after verifying the chokeplate is fully closed, inspecting the spark plug is theeasiest way to confirm that fuel is being delivered. Ifthe spark plug is not wet with gasoline after repeatedattempts to start the engine, it indicates that fuel isnot being delivered. An extremely wet plug mayindicate that the choke could be stuck closed or theengine has been over-choked or over-primed.

Fig. 4

Fig. 5

Fig. 6

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In excess of 95% of all (carburetor) performance problemsare caused by dirt or debris in the system.

Most performance problems are described as “hunting and surging” in various modes of operation. Huntingand surging at idle, top no-load or under load make up the majority of customer complaints.

A challenge in diagnosing performance problems in a carburetion system is deciding whether you have agovernor problem or a carburetor problem. With this in mind, the first test for a technician is to differentiatebetween the governor and carburetor systems.

Performance issues are the most common carburetion problems seen in the day to day operation of a repairfacility. Performance problems come in many varieties. We will cover the most common symptoms and therecommended procedures for successfully troubleshooting the problem.

� Engine won’t idle – hunts and surges/runs poorly at idle

� Engine hunts and surges/runs poorly at top no-load speed

� Engine hunts and surges/runs poorly under load

In many of these cases, the common problem is a lack of fuel or “lean” condition as opposed to an overly richcondition. Most hunting, surging and performance problems can be directly attributed to an obstruction offuel flow.

SEPARATING THE GOVERNOR SYSTEM FROM CARBURETION SYSTEMSeparating a possible governor problem from a carburetor problem can be different for each complaint orcombination of complaints. This is where the use of carburetor theory becomes very important. To begin thetroubleshooting process, make sure the governor system, linkage and spring(s) are in the proper positionsand orientations without interference from sticks, grass or other debris. Some engines have multiplepositions for the governor spring. Any deviation from the correct position will cause symptoms that aredifficult to accurately diagnose and correct.

Once the governor system is inspected for obvious problems, the next step is to check the static governoradjustment. The procedure is in the repair manual for the engine series you are working on.

TROUBLESHOOTING CARBURETION SYSTEMSPERFORMANCE PROBLEMS

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TROUBLESHOOTING CARBURETION SYSTEMS

ENGINE HUNTS & SURGES AT TOPNO-LOAD SPEED (ONLY)To determine if this symptom is caused by acarburetor or governor problem, follow the sameprocedure described for hunting and surging atgoverned idle speed.

Once the idle mixture adjustment is performed (if soequipped) and the engine idles smoothly, increasethe engine speed using the idle speed screw. Youmust hold the throttle plate linkage against the idlespeed adjustment screw until the engine reaches itstop no-load speed.

Keep in mind that without any appreciable load, thecircuit providing the fuel is the idle/transitionalcircuit.

HUNTS and SURGES AT IDLE (ONLY)An engine that hunts and surges at true idle (whenthe linkage is against the idle speed adjustmentscrew and after idle mixture adjustment) can only becaused by a fuel delivery problem or an air leak.

Because the throttle plate is held stationary in thecarburetor bore, a rhythmical hunting & surgingproblem must be caused by an improper air/fuelmixture related to an air leak or an obstruction in theidle circuit.

The reasoning behind this statement is that at trueidle, the governor has no effect on the engine at all.The governor spring produces no force at true idle.

ENGINE HUNTS and SURGES ATGOVERNED IDLEPerform an idle mixture adjustment (if so equipped).

To separate the governor system from the carbure-tor at governed idle speed, hold the throttle platelinkage against the idle speed adjustment screwand increase the idle speed to the governed idlespecification. If the engine runs well without anyhunting or surging, return the engine to the correcttrue idle speed.

Next, bring the engine up to the proper governedidle speed using the governed idle spring. If thehunting and surging returns, chances are good thatyou have a governed idle spring or linkage problem.

Fig. 7

Fig. 8

Fig. 9

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TROUBLESHOOTING CARBURETION SYSTEMS

HARMONIC HUNTING AND SURGINGIt is possible that at some speed settings, the governor spring could begin to vibrate excessively. This canresult in very unstable governing. To test for this rather uncommon but possible problem, run the engine atthe speed that it hunts and surges the greatest. Observe the motion of the spring. If the spring seems to beoscillating or vibrating excessively, take a pencil and place the eraser end lightly against the vibrating spring.This should dampen the vibration. If the hunting and surging disappears, replace the governor spring withthe exact part number dictated by the model, type and code numbers of the engine.

ENGINE HUNTS and SURGES AT TOP NO-LOAD SPEED (ONLY) CONT.If the engine continues to hunt and surge, chances are good that the carburetor is causing your problem.The reasoning behind this is that with the idle speed screw controlling the throttle plate position (thereforethe engine speed) the governor has no real effect on the performance of the engine.

If the engine runs well while controlled by the idle speed screw but continues to hunt and surge while beingcontrolled by the governor spring, the governor system would then be suspect. Check the governor linkagefor resistance or binding then replace both the governed idle and the main governor springs.

ENGINE HUNTS and SURGES UNDERLOAD (ONLY)The chance of a governor system causing a huntingand surging condition under load is very remote.The reason for this is that when the carburetordelivers fuel under load, it is feeding fuel almostexclusively through the main nozzle. Most loads areconstant enough to maintain the rpm of the engine.Once the engine is doing work, the governor systemhas little additional effect on the performance of theengine.

Fig. 10

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TROUBLESHOOTING CARBURETION SYSTEMSCOMBINATION SYMPTOMS

There are times when an engine will exhibit multiple symptoms. This is where your troubleshooting skills willbe tested time and time again. It is important to remember basic carburetor theory while performing yourtests.

Multiple symptoms tend to follow a pattern in which common combinations are found.

ENGINE HUNTS and SURGES AT IDLE andTOP NO-LOAD; RUNS WELL UNDER LOADAn engine that exhibits these symptoms and runswell under load is a classic example of whereunderstanding carburetor theory will help in thediagnosis.

The circuit that is feeding the fuel to the engineduring idle and top no-load is essentially the same,the low speed circuit. If the engine runs well andproduces acceptable power under load, then themain jet, main fuel supply, and main air bleed can bepresumed good. The problem must reside in theidle/transitional circuit.

Carefully check the pilot jet (if equipped) or thetransitional holes for debris.

ENGINE RUNS POORLY UNDER LOADOther than compression component problems(which we have tested and eliminated) an “underload” performance problem is almost exclusivelycaused by debris in the main jet/nozzle or air bleeds.

To assist in determining which of these componentsmay be at fault, examine the exhaust system whilethe engine is under load. If black smoke is evidentwhen the engine becomes symptomatic, chancesare there is an excess of fuel. That would indicatethat there is an incorrect float level setting, a cloggedmain air bleed or debris is lodged between theneedle and seat.

If the exhaust exhibits no smoke, and has no blackresidue on the muffler deflector, chances are that itis the main air bleed or main jet that is obstructed.

Fig. 11

Fig. 12

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TROUBLESHOOTING CARBURETION SYSTEMSPERFORMANCE PROBLEMS – SPECIAL HELP

USING A “KNOWN GOOD” TESTCARBURETORAnother common practice (that is practical in someinstances) is to attempt to confirm a carburetorproblem by installing a known good carburetor onthe engine.

Taking into consideration shop labor rates, the timeto remove and replace the component as well as thecost of the carburetor may make the practice oftroubleshooting smaller carburetors impractical.

USING THE CHOKE AS A DIAGNOSTICTOOLUsing the choke as a diagnostic tool is one of thequickest and easiest methods of determiningwhether you have a lean condition causing yourperformance problem.

After making all possible carburetor adjustments, trySLOWLY closing the choke plate while the engine isperforming poorly. If performance improves, theengine is experiencing a lean condition. If perfor-mance gets worse, you may have a rich runningcondition.

The primer can also be used as a diagnostic tool butwith slightly less accuracy as it is more difficult tocontrol the amount of fuel each pulse supplies.

CLOGGED/DAMAGED MUFFLERSA clogged/damaged muffler or spark arrestor cancause poor performance as well as an apparentcarburetor leak. The classic symptoms of a mufflerproblem are:• Lack of power, difficulty in achieving rpm• Distinct change in exhaust sound level or quality• Gasoline soaked air filter• Noticeable large plume of gasoline vapor around

the carburetor (with the engine running)

To check the muffler for problems, replace themuffler and re-test. (Don’t forget that a looseexhaust valve seat can closely mimic a cloggedmuffler).

Fig. 13

Fig. 14

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Carburetor leakage problems typically fall into three categories:

� Leakage while not running (known as static leakage)

� Leakage while running

� Leakage during/after coast down

When attempting to troubleshoot carburetor leakage problems, it is especially important that you notautomatically assume a component is good or overlook any possible cause. Although an overwhelmingmajority of the leakage is caused by dirt or debris, there is a small percentage of carburetors whosecomponent parts may cause a symptomatic leak. Because of the relatively high return rate for leakagerepairs reported from the field, extra care in proving the integrity of the carburetor is very important toincrease the rate of first time, successful repairs.

TROUBLESHOOTING CARBURETION SYSTEMSLEAKAGE

One of the most annoying problems in the field is that of carburetor leakage. Many years of research havegone into effective remedies for this problem and true factory defects are very uncommon. It has beendetermined through testing, that a large portion of the carburetors returned to Briggs & Stratton for warrantyconsideration have been found to be structurally acceptable. Most carburetors that are returned from thefield have been contaminated with dirt, debris or water.

The overwhelming majority of carburetor leaking problems are caused byDIRT OR DEBRIS.

Fig. 16

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POROSITY/EXTERNAL LEAK TESTTo test a carburetor for porosity or external leakage,invert the carburetor and submerge in a water bath.Hold the float with a finger to assure a seal betweenthe needle and the seat. Pressurize the inlet needleto at least 8 psi (55 kPa). If there is porosity in thecarburetor, bubbles will be present, erupting fromthe casting between the brass seat insert and themetal casting or from the fuel inlet fitting.

Caution: Excess finger pressure will cause damageto the needle and/or seat surface. The viton portionof the needle and seat combination should bereplaced after performing this test.

LEAKAGE WHILE STATICTo tell where a static leak is occurring, remove thecarburetor from the engine and remove the floatbowl. Invert the carburetor with float and needleinstalled. Wet the needle and seat area with a smallamount of gasoline. Use the “thumb type” pump(with clear non-rubber hose) to pressurize the inletneedle to a minimum of 8 psi (55 kPa). The inletneedle should pop off and re-seat at 2 psi (14 kPa)or greater. If the needle does not seal, clean orreplace and test again. If the needle seals and holdspressure at 2 psi (14 kPa) or greater for at least 5minutes, consider it acceptable. If the carburetor stillwill not hold 2 psi (14 kPa) for 5 minutes or continuesto exhibit a leak when the engine is in service,additional testing is indicated.

TROUBLESHOOTING CARBURETION SYSTEMSFLOAT STYLE CARBURETOR LEAKAGE WHILE STATIC

To help technicians more accurately diagnose the true cause of a leaking carburetor, the CustomerEducation Department has put together some procedures and specifications for all of our float stylecarburetors.

Briggs & Stratton CarburetorSpecifications/Procedures (All Types)

Needle/Seat minimum sealing pressure: 2 psi (14kPa) (wet with fuel) for minimum of 5 minutes

Static test 2 qt. (1.9-2L) fuel tank: 12”-18” (30-45cm) above the inlet fitting

The tools suggested by Briggs & Stratton to perform the following troubleshooting tests are:Walbro 4 cycle “thumb pump” part # 57-21, McCulloch carburetor pump part # 215432 or a similarequivalent.

Before testing a float style carburetor with air pressure, be sure that the float assembly contains no liquid.Any retained liquid causes increased weight and reduced buoyancy.

Fig. 17

Fig. 18

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SUCCESSFUL FIRST TIME REPAIR TIPSTo maintain a high level of success repairing leakingcarburetors caused by dirt or debris, the first place tostart is the fuel supply. The fuel tank should bedrained completely and inspected for debris, dirt orscaling (if the tank material is metal). Clean orreplace as indicated.

After confirming the integrity of the tank, remove allfuel lines and filters and replace with new. It is highlyrecommended that fuel filter part #493629 be usedin all but a few rare instances.

The only instance where the #493629 filter shouldnot be used is when the fuel supply is gravity feedand the bottom of the fuel tank is less than 1”(2.5 cm) above the inlet fitting of the carburetor.

TEST RESULTSIf the pressure test reveals no bubbles from anycomponent parts, check the float carefully byimmersing it in warm water and watching for bubbleserupting from a seam. If all components test good, itis safe to assume that the original leakage problemwas cased by dirt or debris.

To effect a repair that will retain a high level ofquality, it is important to follow the next steps withoutdeviation.

INLETSEAT

CAVITY

GO THE DISTANCEIt is important to go the distance and remove every“removable” internal part and check for dirt or debris.Many well intentioned repairs have returned to theshop due to dirt hiding in some small, difficult toexpose area of the carburetor.

If the inlet seat in the carburetor body is removable,do so, especially in the case of a chronic or repeatedleak. Check in the repair manual for the properprocedures. Dirt and debris can hide behind the seatand, if disturbed, may cause leakage at any futuretime. If any dirt or debris is found, all (removable/re-placeable) jets, air bleeds and pilot jets should becarefully checked, cleaned or replaced.

TROUBLESHOOTING CARBURETION SYSTEMSFLOAT STYLE CARBURETOR LEAKAGE WHILE STATIC

Fig. 19

Fig. 20

Fig. 21

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Fig. 22

DON’T CAUSE YOUR OWN LEAKOne last service tip may help relieve some problemsseen in the field. When a fuel filter is removed, asmall amount of the inner rubber hose is rolled up asthe barbed end of the filter is pulled out. This smallamount of rubber can find its way into the carburetorand cause obstructions as well as leaks. The debrisis very small and difficult to see with the naked eye.Whenever you remove a fuel filter, replace the fuelline. Especially if the carburetor has exhibited achronic leak.

Never use a bolt or threaded object to plug a fuel lineduring repair. The threads will cut the rubber hoseand aggravate the debris problem. Fig. 23

STATIC LEAK TESTOne method used successfully in the field to staticleak test a carburetor is done with a simple 2 qt.(1.9-2L) free standing tank. Fill the tank withgasoline and place it between 12” and 18” (30-45cm) above the test bench measured from the bottomof the fuel tank. Attach the fuel line to the carburetorto be tested and open the in-line fuel shut off. SeeFigure 22. Place a piece of paper under thecarburetor and let it stand in a large catch basin ordrain pan. The carburetor should not exhibit anyleakage if left to stand overnight.

TROUBLESHOOTING CARBURETION SYSTEMSFLOAT STYLE CARBURETOR LEAKAGE WHILE STATIC

An engine that exhibits leakage after it sits for a period of time can be caused by a number of problems. Themost common of these is dirt. Any imperfection on a needle or seat surface, such as a small particle of dirt,can cause an engine to perform well in all other scenarios but still leak after sitting a period of time. Inaddition to dirt, an improperly vented fuel cap can allow pressure to build in the tank which could overcomethe float assembly and result in a sporadic leak.

All fuel filters are rated by the size of the particle they will allow to pass. If the filter size is too large, debriscapable of plugging the jets will enter. If the filter size is too small, the fuel flow will be reduced and may causean engine to run lean.

When an engine is not in use, the fuel in the bowl is exposed to the atmosphere via the bowl vent. Fineparticles of dirt or debris that normally would be suspended in the fuel and pass completely through thecarburetor, settle out and end up at the lowest point between the fuel inlet fitting and the inlet needle. As thefuel slowly evaporates, the float responds by lifting the inlet needle very slightly off its seat. The dirt presentmoves in and lodges itself between the needle and seat. Now a slow but steady flow continues into the bowl,eventually showing up as a static leak.

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TROUBLESHOOTING CARBURETION SYSTEMSFLOAT STYLE CARBURETOR LEAKAGE WHILE RUNNING

There are some situations that could cause a symptom of leakage while operating. These are rare and canbe challenging to troubleshoot accurately. Most cases of leakage during operation can be attributed to thesame problems that cause static leakage. There are however, additional possibilities when it comes to thisscenario. It should be noted that there are two types of leakage while running.

The first type of leakage is external. This could be caused by deteriorated tank and strap assemblies andloose, torn or missing external gaskets (adjustment nut packings or bowl nut washer etc.). The second typeof leakage is internal. A symptom of this would be an engine that displays a leak through the brass “drain”insert in the throat of the carburetor or “wets” the air cleaner element with fuel. This type of leakage can becaused by any number of problems:

� Loose or damaged main nozzle (2 piece flo-jet)

� Clogged air filter element (externally vented carburetors only)

� Excessive vibration

� Incorrect fuel inlet seat size

� Improper float level

� Clogged muffler

� Porosity in the carburetor casting

� Improper valve clearance

� Intake valve seat loose

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TROUBLESHOOTING CARBURETION SYSTEMSSPECIFIC CARBURETOR TROUBLESHOOTING – REPAIR TIPS

TWO PIECE FLO-JET LEAKAGEThe two piece flo-jet carburetor has a unique designthat can cause some misunderstandings in the field.This carburetor has a main nozzle/jet that bisectsthe carburetor body. Near the base or large end ofthe main nozzle/jet tube is a chamfered area thatprovides a seal between the emulsion cavity and thefuel bowl of the carburetor. If there is any defect, dirtor corrosion on the surface of the sealing area(either the brass tube or carburetor casting) thecarburetor could exhibit a leak. The symptomsinclude: unexplained and inconsistent leakagewhile at rest, leakage during long coast downperiods, poor overall performance.

TWO PIECE FLO-JET LEAKAGE (cont.)If the sealing area integrity is in doubt, take the oldnozzle and remove the threads with a bench grinder.Place a small amount of lapping compound on thenozzle at the taper and insert it into the body of thecarburetor. With a jet screwdriver, gently lap thenozzle just as you would when you lap a valve in.Remove the old nozzle and clean the carburetorbody completely.

Using a new nozzle/jet, install the Teflon washerfrom a # 391413 carb repair kit over the tube andseat it on the sealing surface of the new nozzle andinstall. The Teflon washer acts like a gasketproviding a better sealing surface for both thenozzle/jet and the body of the carburetor.

BENCH TESTYou can quickly and easily bench test this condition.Install the nozzle/jet assembly into the lower carbu-retor body. Thread a 1/4” bolt into the base at thespeed control bracket boss to use as a “handle”.Grip the bolt head in a vise and position the body sothat it is level. See Figure 25.

Add fuel to the bowl until it is three quarters full. If thetapered sealing area is intact, there will be no fuelleakage into the carburetor throat.

Fig. 24

Fig. 25

Fig. 26

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ADDITIONAL SERVICE TIPS

� The proper and thorough cleaning of a float style carburetor includes the removal of all partsincluding the welch plugs (on larger carburetors).

� The use of commercial carburetor cleaners is limited to a total soaking time of 30 minutes.

� Always use good quality carburetor spray solvents with long nozzles. These help immensely inreaching internal orifices and passageways.

� Always wear eye protection when cleaning a carburetor. The spray from the aerosol can easily bedeflected and get into your eyes.

� The removal, cleaning and inspection of the inlet seat area is critical for optimum performanceespecially in chronic leakage cases.

� Always install new fuel lines and fuel filter (#493629 recommended) when repairing a unit with acarburetion system leak.

� Always instruct the customer to use the fuel shut off valve when transporting the equipment. If theunit does not have a shut off valve, install one.

� Always clean your hands and work surface before starting any carburetor repair.

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Notes

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