Walbro Carburetor Service

Walbro has created this great video on 2-cycle carburetor service.  We could’t have done it better ourselves.  If you have questions or comments please feel free to contact us using the comments section below or our contact form.

Transcript Provided by YouTube

0:11 hi always sells program manager for Walbro

0:14 and on and on

0:16 Business Unit Manager this video is intended to help you inspect a service

0:20 Walbro die from carburetors

0:22 whether the butterfly for rotary valve models that you know down while changes

0:27 in our industry have affected curb your service

0:29 the induction about the longer a fuels affects the curb your operation

0:33 and tempers and features well as the amato just like in users can make to the

0:38 carvers today

0:39 we’re gonna discussed these topics along with us

0:42 inspection and service a diaphragm harbors in this video

0:46 a basic understanding the Currier function will be very handy for this

0:50 video so let’s start there

0:55 the covered us three important task first

0:58 fuels drawn from the gas tank into the Currier second

1:02 fuels meter to match the engine’s RPM and load requirements

1:06 and finally the metered amount of fuels mix with their

1:10 and delivered to the crankcase at the proper time in the engines operating

1:13 cycle

1:14 to control the full fuel an air into the engine

1:17 the car uses pressure created within the engines crankcase

1:21 known as an impulse the movement of the piston crease to total impulse

1:26 a negative impulse or vacuum is created during the Pistons upward stroke

1:32 all positive impulses generated by the Pistons downward motion

1:35 the samples are delivered to the Currier

1:39 through sheen channels in a manifold or Temple City

1:42 the channel surf innings lead to the Field Poll

1:45 the car through contains the throttle valve and some models

1:49 the job well

1:55 that’s good for you

1:56 think I’ve got a car but a problem where do I start done whenever you have a car

2:00 rear any type that seems to be malfunctioning

2:02 the first one eliminate any potential causes the not directly related to the

2:06 car rear

2:07 always use fresh fuel based on the engine manufacturer’s recommendation

2:11 engine problems resulting from

2:14 ban spark plugs o’clock muffler low compression can also be misinterpreted

2:19 discovery problems

2:20 so be sure to include these areas in your initial engine special procedures

2:25 then checked the fuel tank vent and the fuel filter for obstructions

2:29 debris in either area could easily cause the fuel delivery problem if the filter

2:35 is dirty

2:36 clean or replace it with an original Walbro fuel filter

2:40 with the tank inventor clear disassemble and inspect the air

2:43 filter because curriers depend on adequate airflow

2:47 a clogged filter could result in overly rich condition

2:50 next check the fuel and primer lines

2:55 sure they are pinched plugged or cut

2:58 your initial inspection should also include a pressure checked all the fuel

3:03 line in the Currier

3:05 pressure testing the carburetor reveals the operating condition

3:09 the inlet Neil connector water pressure tester part number fifty seven days you

3:15 have it

3:15 to the fuel line apply air pressure by slowly pressing the plunger

3:20 to gauge will indicate an increase in pressure

3:24 until the inlet needle valve 1 seeds this level was referred to as the pop of

3:30 pressure

3:30 and may range from 15 to 50 PSI

3:33 due to the variety of carburetor design specifications

3:37 occasionally the inlet needle valve will not on C

3:40 in this case you’ll need to disassemble the carburetor

3:44 which will get into in just a bit after popping off

3:47 the games will drop to indicate the pressure it was the inlet valves we

3:51 seeds

3:52 this is referred to as the recent pressure the inlet legal should we see

3:56 and hold a minimum

3:58 a5 PSI complete the pressure checked by performing the same test

4:03 at the curriers fuel inlet if pressure test show property law operation

4:07 it’s time to check the curry among area and the manifold gasket

4:11 connecting the carburetor to the engines crankcase for where damage

4:15 be sure to inspect the impost passage leading to the fuel pump chamber

4:20 crankcase impulses must be able to reach the car we report operate properly

4:24 to test put a drop a boil over the passage

4:28 crank the engine a few times and watch the oil

4:32 if the oil doesn’t move only moves slightly

4:35 the passages blocked it must be clear

4:41 if the engineer working on has a readout checked about

4:44 it should be free debris improperly aligned with the intake port

4:49 we should note that everything we’ve talked about so far

4:52 applies to all types a diaphragm carburetors but now

4:56 we want to look specifically at servicing the two major types of Walbro

5:00 diaphragm carburetors that are used in hand-held equipment

5:03 ballroom manufactures a variety of butterfly valve carburetor models

5:07 yes components are all very similar well see how a butterfly valve carburetor

5:12 functions

5:13 the butterfly Welker can be divided into three basic

5:16 a resume operation the fuel palm

5:20 the fuel meter area and the problem ok well

5:24 the fuel pump is made above a copper

5:28 a gasket a diaphragm

5:31 and the pumps I to the curb your body the pump is activated by crankcase

5:36 impulses

5:37 delivered through machine chair or temple said the meter its site also

5:41 includes a fuel inlet screen

5:43 the in with your fist

5:50 the and let you know and the fuel metering chamber

5:53 the mir in chambers made a book cover

5:57 a meter a diaphragm a gasket

6:00 a metering lever PID and spur

6:05 and nozzle check out and the i/o some blue located within the Currier body

6:09 and the Iowa just as for the final area

6:13 about operation close the choke and throttle valve assemblies

6:16 the throttle valve assembly is made above a shop

6:20 lever assembly spring in Val the choke is made a push app

6:26 the liver assembly Chopra chill all spring

6:30 in about the motor fuel delivery to the crankcase is determined by the position

6:36 on the throne about

6:37 the more open the veil the more airflow

6:41 the more airflow the greater amount of fuel delivered to the crankcase

6:48 well

6:49 a lot of good information it is down because a basic understanding of the

6:53 butterfly valve covers function

6:55 will come in handy as we expected for proper operation

6:58 so let’s get started getting to the proper procedure for inspecting the

7:02 butterfly bill Currier

7:03 before you begin inspecting the career be sure the mir in fuel pump areas are

7:08 completely disassemble

7:09 I’ll professionals and she needed to the carburetor by

7:13 these passages are accessible through a Wallflower

7:17 to remove the Welsh club used to remember 516

7:22 available on both the 400 dash 595

7:25 and 500×500 war virtual kiss

7:29 position the sharp end of the tool and a slight angle

7:33 and tap the 2012 a pennant race the world clock then apply light pressure to

7:38 the handle

7:39 into the plug pops up be careful not to contact or damage to carburetor body

7:43 with the tool

7:44 once the curriers disassembled clean the entire body and its covers

7:50 use meryl Spears to avoid damage to cover your part

7:54 and blow dry with approximately 25 PSI

7:57 compressed air be sure all holes and passes

8:01 are clear

8:03 on models with the check out the has a novelty whole

8:06 you can verify the nozzle check valves operation with a small holes for fuel

8:10 line

8:11 position the holes are feelin over the metering chamber cider the now

8:15 then draw the nozzle check valve up against a retainer

8:19 two or three times to ensure its operating properly do not use a metal

8:23 tool to clear the nozzle

8:25 now we can reassemble the car we’re beginning by installing the Wells Fargo

8:29 using tool number 515 align the well-spoken position a tool

8:36 on the dope are the clock

8:40 then tap the plug until becomes plaque

8:42 it’s important that the plugins class so it doesn’t interfere

8:46 with the functional meet your diaphragm simple moving in the past I remember

8:51 using nail polish

8:52 still the most blogs yes dan is true however because about the of fuels we no

8:57 longer use for help I was really cuz she on

8:59 on the walls close we found ethanol fuels can dissolve the CEO and create

9:03 other problems

9:04 now we can reassemble the inlet needle me real ever

9:08 pin spring and lever pin screw

9:12 next check the liver height adjustment with locals meter gauge number 530

9:21 position to gauge across the Currier body the cage just contact the metering

9:26 lever with

9:27 out hoping they didn’t need allow if the levers mysoline

9:32 use a small screwdriver to keep the head of the inlet legal stationery

9:37 at the same time slide another small screwdriver tulip

9:40 or depressed the mir lever arm toes properly adjusted

9:46 this would be a good time to check the function of the inlet needle with me to

9:50 recover

9:51 metering diaphragm assembly removed apply pressure to the fuel inlet fitted

9:55 and manually depress the metering lever to ensure that the inlet needle moves

9:59 freely

10:00 if it does a disassemble the metering system completely

10:03 and carefully clean up arms walk through small parts clear part number:

10:08 500 as 520 we’re hoping Clinton sparks

10:11 carefully inspect needle tip

10:14 and announcers will see for debris or damage before reassembly

10:18 if you working on an older car burger with the circuit plate design

10:22 inspect a certain play end gasket for signs of damage or wear

10:26 the holes in a certain way it should be free of any obstructions

10:29 next replace the murine diaphragm and gaskets using

10:33 original water parks

10:39 we understand that the likelihood of damage to soft parts in the carburetor

10:43 as greater with ethanol fuels right now well over continue developing advanced

10:49 engineering materials that are highly resistant

10:51 ethanol ethanol fuels 10 affects of course like diaphragms

10:55 your palms and gaskets on of her readers plus

10:58 ethanol traction waster causing corrosion on the woman Mars

11:02 and moisture in the fuel also reduces shelf life so

11:07 how can we avoid problems first use the fuel

11:11 recommended by the engine manufacturer second make sure it’s fresh

11:15 and finally run the fuel other equipment if it’s going to be six weeks or more

11:20 before you use it again

11:21 great tips for me tax let’s continue our butterfly valve carburetor inspection

11:27 reassemble the fuel Paul beginning with new fuel inlet screen

11:31 fit the new screen into the screen pocket and pressed to the screen pocket

11:36 step

11:36 using Walbro to a number 515

11:40 the strange completely contact the casting wall

11:44 next resemble the pump diaphragm

11:48 gasket car cover and covers true

11:51 if you need the car rear components or damage

11:54 replace them with original over parts but generic exploded view

12:00 analyst at all the covers specific personally found

12:03 atwater’s web site WWW dot Walker not calm

12:07 before reinstall pressure just the car here as we discussed in the initial

12:12inspection section

12:13 to ensure it is that probably reassemble if the car we’re past the pressure test

12:18 it can now be reinstalled on the engine and check for proper adjustment

12:28 fully understand the car

12:29 your adjustment procedures have changed to accommodate near carburetors

12:33 with tamper resistant features that’s right due to environmental concerns

12:37 since the mid-nineties careers have come quick from the manufacture

12:41 with tamper resistant features of various kinds these features limit the

12:45 amount of adjustment available

12:47 to consumers in order to maintain low emissions the tools techniques and

12:51 specifications needed to adjust these carburetors are available to authorized

12:55 dealers

12:56 directly from the engine manufacture however

12:59 resale these tools to consumers carriers heavy penalties

13:03 on all carburetors camp resistor not you can still adjust the idle speed screw

13:08 refer to the manufacturer’s recommendations percent

13:14 that covers the operation troubleshooting and adjustment

13:17 wawrow butterfly valve carburetors further servicing information

13:21 an ample supply original replacement parts can be obtained measure Walbro

13:26 distributor

13:27 while remaining factors various versions a rotary dial carburetors

13:31 the carvers differ somewhat design

13:34 the components can still be grouped into three basic theories about Operation

13:38 the fuel call the metering area

13:42 and the throttle shaft assembly moseley’s purveyors also come equipped

13:47 with their own primer

13:49 let’s take a closer look at the components that make up the rotary valve

13:52 covers three functional areas

13:54 and their attentions the first functional area includes the fuel Paul

13:59 far beneath the primer pump assembly the fuel pump is made a public gasket

14:05 a diaphragm

14:07 pump body assembly and the palm side to the carburetor body

14:11 removing these components also reveals a fuel inlet screen

14:16 an inlet new yorkers the carburetor body also contains a channel which allows

14:21 crankcase

14:22 impose to enter the field poll the meter near is made above the inlet we’ll see

14:27 the main nozzle check Val

14:31 a metering diaphragm assembly the meal ever

14:35 Penn sprint and Ian MacNeil

14:38 piano and he was held in the closed position by the force in the spring

14:42 against the lever

14:43 summary Valkyries may contain a service Balmain jet

14:48 the final area of operation is a trial area

14:51 to worry throttle barrel assembly includes the parallel

14:55 needle spring throng RAM

15:00 idle screw bracket I’ll adjustment screw

15:04 swivel and throttle lever most evolved rotary valve covers come equipped with a

15:09 prime system

15:10 the systems are designed purchases among their

15:14 an assist the car rear during star the primers made above the purge body

15:18 assembly

15:19 cover and primer ball and number on a check valve that controls the flow of

15:24 you want their

15:25 during the primary now operation depressing the primary ball

15:29 opens the outlet czech girl alone area fuel to exit the mall

15:33 has the ball returns to shape a vacuum is created

15:36 hoping the fuel inlet valve causing fuel to circulate throughout the carburetors

15:41 fuel circuit and into the ball

15:43 a normal circumstances the ball should only have to be depressed four to five

15:47 times to properly prime the system

15:53 to inspect your

15:54 out carvers begin by performing an initial general inspection of the area’s

15:58 surround the Currier including air filter

16:01 muffler spark plug

16:05 fuel filter and few holes

16:08 if no problems found the car burger must be disassembled

16:12 as you disassemble the carburetor note the order position on the components

16:17 this will help you correctly reassemble career after its been inspected

16:21 start the disassembly procedure at the primer pump assembly

16:25 just below the primer simply is the meter area

16:28 which consists of them you’re a diaphragm assembly a gasket

16:33 and the metering lever pair spring

16:36 and they let me go leave the inlet needle

16:40 lever pin and spring assemble within the pump body assembly

16:44 unless they require replacement removing the fuel pump body is also the first

16:49 epic disassembling the fuel Paul

16:51 the fuel pump insists that the body a diaphragm

16:55 a pump gasket the fuel pump side to the carburetor

16:59 the pump body assembly contains a fuel inlet screen

17:02 and the only the orifice the fuel pump sign the carburetor body also contains

17:07 the main jet and soaring

17:09 once the curriers completely disassemble

17:13 clear smoke components using mineral spirits now to finish cleaning the

17:18 components it’s time to reassemble the carburetor

17:21 begin by reassembling the main gibbering

17:25 and main jet into the palm side of the body install a fuel inlet screen in the

17:29 fuel pump cover using to number five hundred asked

17:32 15 the screen should be pressed to the screen pocket step

17:36 and fit flush with the pocket wall reassemble the meter area using original

17:42 Waltrip ours

18:11 check the liver height adjustment Wow

18:13 we’re engaged number 513 E and adjust as needed

18:17 you have the option to replace the entire fuel pump by recently as a

18:21 replacement unit

18:22 this simplifies replacement any limits the need

18:26 for the mir leid wir height adjustment now reassemble the fuel pump body

18:30 assembly

18:31 to the pumps I to the car rear body using a new gasket and diaphragm

18:38 the final air tour inspected reassemble is the primer pump assembly

18:41 reassembled using the gasket diaphragm

18:45 purge body bobbin cover

18:52 if the

18:53 valve doesn’t see properly or the prime rib all doesn’t return to shape

18:57 replace the entire primer pump assembly what you completely reassemble the

19:02 Currier it must be pressure test again

19:04 the procedures the same as we use in the initial inspection

19:07 and also for the butterfly valve covers using your water pressure tester number

19:12 57 issue 11

19:13 determine the valve pop off increasing pressure settings

19:16 be sure the inlet your valve is wet before you pressure tester

19:20 the gauge will indicate an increase in pressure until the inlet needle valve in

19:25 seats

19:26 the inlet the ocean and sea between 15

19:29 260 PSI depending upon the covers design specifications

19:33 this level was referred to as the pop of pressure

19:36 the gate will then drop to indicate the pressure

19:39 where the inlet valve 3 C’s this is also referred to as

19:43 3c pressure without increasing at a minimum

19:47 a5 PSI if the car rear passes the pressure test

19:51 they can be reinstalled on the engine and checked for proper just one

19:59 as we discussed with butterfly valve carburetors carburetor adjustment

20:02 procedures

20:03 are different now because newer carburetor September existing teachers

20:07 that’s right since the mid-nineties card readers have come equipped

20:12 from the manufacturer with campers and features various types

20:15 these features are designed to limit the amount of adjustment possible by

20:19 consumers

20:20 if you’re an authorized dealer the tools techniques and specifications necessary

20:25 to adjust these purveyors

20:26 are available from the engine manufacturer however these cannot be

20:30 solved consumers

20:31 without the risk of heavy fines I’ll cover your stamp resistor now

20:36 you can adjust the idle speed screw just refer the engine manufacturers

20:40 recommendations for the sentence

20:44 congratulations this concludes the operation

20:47 repair an adjustment Walbro rotary valve carburetors

20:51 for more information on servicing over a diaphragm curriers

20:54 the location years authorize water distributor

20:57 and other information about Walter and its products was our website at WWW dot

21:03 wallpaper dot com

21:04 and don’t forget to use authentic Walbro replacement parts

21:08 for results you can count on thanks thanks for watching

We carry a large selection of Walbro Carburetor Parts. If you need help finding your Small Engine Parts, please complete the Lawn Mower Parts Request Form and we will be happy to assist you.


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Jack Hayes

Jack Hayes

Jack Hayes is the Head of Internet Marketing at LawnMowerPros and the editor of this blog. You can often find him creating featured articles, DIY guides, custom graphics and much more.