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Repair Parts Home    Lawn Equipment Parts    Husqvarna Parts    Husqvarna Blower Parts    Husqvarna Handheld Blower Parts    Husqvarna 125BT (2004-05) TH026D-AC57, Handheld Leaf Blower Parts
Husqvarna 125BT (2004-05) TH026D-AC57, Handheld Leaf Blower

 Husqvarna 125BT (2004-05) TH026D-AC57, Handheld Leaf Blower Parts

 Fig # Part # Img Part Name Availability Price Qty
A-5310095-42531009542
Gasket
Ships in 5 - 7 business days
 $1.21
A-5310095-42531009542
Gasket
Ships in 5 - 7 business days
 $1.21
A-5310095-43531009543
Plate
Ships in 5 - 7 business days
 $4.39
A-5310095-44531009544
Spacer
Ships in 5 - 7 business days
 $6.27
A-5310095-45531009545
Gasket
Ships in 5 - 7 business days
 $1.21
A-5310095-46531009546
Screw
Ships in 5 - 7 business days
 $0.40
A-5310095-47531009547
Holder
Ships in 5 - 7 business days
 $24.03
A-5310095-48531009637
Air Filter Element
In stock
7 available
 $4.86
A-5310095-49531009549
Cover Obsolete - Limited Quantity
In stock
1 available
 $7.52
A-5310095-50531009550
Knob Obsolete - Limited Quantity
In stock
1 available
 $2.62
A-7241331-01724133101
Screw Crpanm
Ships in 5 - 7 business days
 $0.54
A-7312314-01731231401
Hexagon Nut
In stock
3 available
 $1.23
B-5310044-36531004436
Gasket
In stock
2 available
 $2.93
B-5310044-38531004438
Gasket
In stock
2 available
 $2.18
B-5310044-42531004442
Lever
Ships in 5 - 7 business days
 $2.53
Fig #Part #ImgPart NameAvailabilityPrice
B-5310044-43531004443
Filter
In stock
2 available
 $1.58
B-5310044-44531004444
Cover
Ships in 5 - 7 business days
 $5.08
B-5310044-46531004446
Float Valve
Ships in 5 - 7 business days
 $8.15
B-5310044-48531004448
Plate Obsolete - Not Available
Discontinued
$0.00N/A
B-5310044-50531004450
Lever
Ships in 5 - 7 business days
 $3.92
B-5310044-52531004452
Diaphragm Obsolete - Not Available
Discontinued
$0.00N/A
B-5310044-53531004453
Diaphragm
In stock
2 available
 $4.69
B-5310044-54531004454
Ring Obsolete - Not Available
Discontinued
$0.00N/A
B-5310044-55531004455
Primer Obsolete - Not Available
Discontinued
$0.00N/A
B-5310044-56531004456
Screw
Ships in 5 - 7 business days
 $1.57
B-5310044-57531004457
Screw
Ships in 5 - 7 business days
 $2.25
B-5310044-58531004458
Screw
Ships in 5 - 7 business days
 $1.68
B-5310044-59531004459
Ring
Ships in 5 - 7 business days
 $1.04
B-5310044-60531004460
Pin Retaining Screw
Ships in 5 - 7 business days
 $1.09
B-5310044-61531004461
O-Ring
Ships in 5 - 7 business days
 $2.13
Fig #Part #ImgPart NameAvailabilityPrice
B-5310044-63531004463
Spring
Ships in 5 - 7 business days
 $1.60
B-5310044-64531004464
Washer
Ships in 5 - 7 business days
 $0.88
B-5310095-72531009572
Carburetor
Ships in 5 - 7 business days
 $122.15
B-5310095-73531009573
Bracket
Ships in 5 - 7 business days
 $7.97
B-5310095-74531009574
Plate
Ships in 5 - 7 business days
 $31.81
B-5310095-75531009575
Jet
Ships in 5 - 7 business days
 $4.87
C-5310095-12531009512
Cylinder
Ships in 5 - 7 business days
 $110.23
C-5310095-13531009513
Gasket
Ships in 5 - 7 business days
 $1.92
C-5310095-14531009514
Crankcase
Ships in 5 - 7 business days
 $54.78
C-5310095-15531009515
Crankcase
Ships in 5 - 7 business days
 $43.76
C-5310095-16531009516
Screw
Ships in 5 - 7 business days
 $0.35
C-5310095-17531009517
Pin Retaining Screw
Ships in 5 - 7 business days
 $0.44
C-5310095-18531009518
Sealing
Ships in 5 - 7 business days
 $2.18
C-5310095-18531009518
Sealing
Ships in 5 - 7 business days
 $2.18
C-5310095-19531009519
Screw
Ships in 5 - 7 business days
 $0.38
Fig #Part #ImgPart NameAvailabilityPrice
C-7382100-10738210010
Ball Bearing
Ships in 5 - 7 business days
 $4.79
D-5032266-01503226601
Nut
In stock
2 available
 $1.99
D-5310037-27531003727
Screw
Ships in 5 - 7 business days
 $0.66
D-5310037-27531003727
Screw
Ships in 5 - 7 business days
 $0.66
D-5310037-27531003727
Screw
Ships in 5 - 7 business days
 $0.66
D-5310037-93531003793
Cover
Ships in 5 - 7 business days
 $35.05
D-5310037-94531003794
Vibration Absorber Obsolete - Not Available
Discontinued
$0.00N/A
D-5310037-94531003794
Vibration Absorber Obsolete - Not Available
Discontinued
$0.00N/A
D-5310037-95531003795
Housing
Ships in 5 - 7 business days
 $86.40
D-5310037-96531003796
Fan
In stock
1 available
 $47.57
D-5310037-97531003797
Housing
Ships in 5 - 7 business days
 $72.06
D-5310037-98531003798
Screw
Ships in 5 - 7 business days
 $0.99
D-5310037-99531003799
Protector
Ships in 5 - 7 business days
 $12.98
D-5310095-01531009501
Screw
Ships in 5 - 7 business days
 $0.47
D-7322514-01732251401
Nut
Ships in 5 - 7 business days
 $0.75
Fig #Part #ImgPart NameAvailabilityPrice
D-7322516-01732251601
Nut Flange - M6
Ships in 5 - 7 business days
 $0.82
D-7322516-01732251601
Nut Flange - M6
Ships in 5 - 7 business days
 $0.82
D-7341154-41734115441
Washer - 26X6.5X1.6 Obsolete - Not Available
Discontinued
$0.00N/A
D-7341154-41734115441
Washer - 26X6.5X1.6 Obsolete - Not Available
Discontinued
$0.00N/A
E-5310033-47531003347
Valve
In stock
10 available
 $11.14
E-5310033-99531-00-33-99
Fuel Cap
Note: Does Not Included the Valve or Seal
In stock
18 available
 $8.60
E-5310044-32531009648
Clamp
In stock
11 available
 $0.50
E-5310044-32531009648
Clamp
In stock
11 available
 $0.50
E-5310044-33531004433
Grommet
In stock
7 available
 $2.53
E-5310095-09531009509
Screw
Ships in 5 - 7 business days
 $0.47
E-5310095-11531009511
Tank Unit
Ships in 5 - 7 business days
 $41.80
E-5310095-58531009558
Filter
In stock
2 available
 $9.68
E-5310095-59531009559
Hose
In stock
2 available
 $1.39
E-5310095-60531009560
Hose Obsolete - Not Available
Discontinued
$0.00N/A
F-5310037-90531003790
Throttle Trigger
Ships in 5 - 7 business days
 $78.81
Fig #Part #ImgPart NameAvailabilityPrice
F-5310044-69531004469
Lever
In stock
1 available
 $3.67
F-5310044-70531004470
Lever
In stock
5 available
 $3.21
F-5310044-71531004471
Shaft Obsolete - Not Available
Discontinued
$0.00N/A
F-5310044-72531004472
Washer
Ships in 5 - 7 business days
 $0.91
F-5310044-73531004473
Washer
In stock
2 available
 $2.09
F-5310044-74531004474
Washer
In stock
2 available
 $1.28
F-5310044-75531004475
Retaining Ring
In stock
2 available
 $0.94
F-5310044-77531004477
Screw
Ships in 5 - 7 business days
 $0.21
F-5310044-83531004483
Screw
Ships in 5 - 7 business days
 $0.33
F-5310095-03531009503
Handle
Ships in 5 - 7 business days
 $17.88
F-5310095-04531009504
Handle
In stock
2 available
 $17.88
F-5310095-05531009505
Cable Assy Obsolete - Not Available
Discontinued
$0.00N/A
G-5310095-06531009506
Harness
Ships in 5 - 7 business days
 $45.40
G-5310095-07531009507
Clip
Ships in 5 - 7 business days
 $1.20
G-5310095-08531009508
Pad
Ships in 5 - 7 business days
 $42.98
Fig #Part #ImgPart NameAvailabilityPrice
G-5310095-10531009510
Frame
In stock
1 available
 $75.36
G-7252368-71544146501
Bolt Flange - M6x20
In stock
3 available
 $0.44
G-7322516-01732251601
Nut Flange - M6
Ships in 5 - 7 business days
 $0.82
G-7341154-41734115441
Washer - 26X6.5X1.6 Obsolete - Not Available
Discontinued
$0.00N/A
H-5032350-11952030150
Spark Plug NGK BPM7A Obsolete - Not Available
Discontinued
$0.00N/A
H-5310032-79531003279
Spring
Ships in 5 - 7 business days
 $0.58
H-5310095-30531009530
Insulation
Ships in 5 - 7 business days
 $1.38
H-5310095-31531009531
Flywheel
Ships in 5 - 7 business days
 $89.19
H-5310095-32531009532
Cap
Ships in 5 - 7 business days
 $1.38
H-5310095-33531009533
Ignition Coil
In stock
1 available
 $89.19
H-5310095-34531009534
Cable
Ships in 5 - 7 business days
 $1.16
H-5310095-35531009535
Cable
Ships in 5 - 7 business days
 $3.11
H-5310095-36531009536
Screw
Ships in 5 - 7 business days
 $0.27
H-5310095-37531009537
Sealing
Ships in 5 - 7 business days
 $1.74
H-5310095-38531009538
Shaft
Ships in 5 - 7 business days
 $11.35
Fig #Part #ImgPart NameAvailabilityPrice
H-5310095-39531009539
Washer
Ships in 5 - 7 business days
 $1.02
H-5310095-40531009540
Screw
Ships in 5 - 7 business days
 $0.15
H-5310095-41531009541
Nut
Backorder:
No ETA.
 $0.22
I-5310095-51531009551
Muffler
Ships in 5 - 7 business days
 $56.50
I-5310095-52531009552
Spark Arrestor
Ships in 5 - 7 business days
 $16.44
I-5310095-53531009553
Gasket
Ships in 5 - 7 business days
 $0.80
I-5310095-54531009554
Ring
Ships in 5 - 7 business days
 $4.29
I-5310095-55531009555
Screw
Ships in 5 - 7 business days
 $0.32
I-5310095-56531009556
Gasket
Ships in 5 - 7 business days
 $4.77
I-5310095-57531009557
Screw
Ships in 5 - 7 business days
 $0.47
J-5310095-20531009520
Piston
Ships in 5 - 7 business days
 $31.81
J-5310095-21531009521
Piston Bolt
Ships in 5 - 7 business days
 $6.94
J-5310095-22531009522
Piston Ring
In stock
2 available
 $12.22
J-5310095-23531009523
Crankshaft
Ships in 5 - 7 business days
 $222.11
J-5310095-24531009524
Washer 7=0,2 Mm
Ships in 5 - 7 business days
 $0.31
Fig #Part #ImgPart NameAvailabilityPrice
J-5310095-25531009525
Washer 7=0,4 Mm
Ships in 5 - 7 business days
 $0.32
J-5310095-26531009526
Washer T=0,6 Mm
Ships in 5 - 7 business days
 $0.31
J-5310095-27531009527
Retaining Ring
Ships in 5 - 7 business days
 $0.54
J-5310095-28531009528
Needle Bearing
Ships in 5 - 7 business days
 $6.67
J-5310095-29531009529
Key
Ships in 5 - 7 business days
 $1.09
K-5310033-58531003358
Plate
Ships in 5 - 7 business days
 $1.09
K-5310033-65531003365
Retaining Ring
Ships in 5 - 7 business days
 $0.22
K-5310033-70531003370
Nut
Ships in 5 - 7 business days
 $0.20
K-5310095-02531009502
Decal
Ships in 5 - 7 business days
 $4.94
K-5310095-61531009561
Pawl
Ships in 5 - 7 business days
 $1.25
K-5310095-62531009562
Cover
Ships in 5 - 7 business days
 $2.17
K-5310095-63531009563
Cover
Ships in 5 - 7 business days
 $13.32
K-5310095-64531009564
Handle
Ships in 5 - 7 business days
 $4.54
K-5310095-65531009565
Pawl
Ships in 5 - 7 business days
 $6.01
K-5310095-66531009566
Starter Pulley Obsolete - Not Available
Discontinued
$0.00N/A
Fig #Part #ImgPart NameAvailabilityPrice
K-5310095-67531009567
Starter Rope
In stock
2 available
 $4.01
K-5310095-68531009568
Screw
Ships in 5 - 7 business days
 $1.09
K-5310095-69531009569
Washer
Ships in 5 - 7 business days
 $0.46
K-5310095-69531009569
Washer
Ships in 5 - 7 business days
 $0.46
K-5310095-70531009570
Spring
In stock
2 available
 $11.54
K-5310095-71531009571
Spring
Ships in 5 - 7 business days
 $1.20
K-7241291-01724129101
Screw
Ships in 5 - 7 business days
 $0.37
L-5310032-12531003212
Clamp
In stock
2 available
 $2.12
L-5310032-13531003213
Pipe
In stock
2 available
 $42.37
L-5310033-75531003375
Holder
Ships in 5 - 7 business days
 $5.92
L-5310037-87531003787
O-Ring
Ships in 5 - 7 business days
 $1.81
L-5310037-88531003788
Pipe
Ships in 5 - 7 business days
 $23.40
L-5310037-89531003789
Pipe
Ships in 5 - 7 business days
 $34.13
L-5310037-91531003791
Pipe Obsolete - Not Available
Discontinued
$0.00N/A
L-5310037-92531003792
Pipe
In stock
1 available
 $22.13
Fig #Part #ImgPart NameAvailabilityPrice

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Discussion
Discussion for the Husqvarna 125BT (2004-05) TH026D-AC57, Handheld Leaf Blower

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1232040
Question: Husqvarna 125b Won't Fire

Meathead

I have a 125b that is has been great for years. I run it weekly and now I can't get it to fire. First, I checked compression and I have 110 lbs. I checked spark and I definitely have spark so I got a carb kit, rebuilt it, replaced fuel lines, checked to make sure filter was clear, replaced the spark plug and put fresh fuel in. Wouldn't begin to start. The plug was wet with fuel, so I went back to check spark again. Definitely getting spark. Put a spark tester on it and it jumps 1/4".

Pulled the flywheel. It didn't appear to be spun and appears to be OK but I'm not familiar with a flywheel that has a key built into it like that. Very hard for me to tell if there's a problem with it or not.

Is there some other way to check the timing or something on this or check the coil some other way? Really baffled and not sure what to do at this point.

Any help would be appreciated.
primerbulb120
Reply: Husqvarna 125b Won't Fire

primerbulb120

Check the muffler. I have had that scenario before: good compression, spark, and a clean carb but the engine doesn't try to start. If you can, just take the spark arrestor off but if it is part of the muffler take the whole muffler off. Keep us posted!
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

Thanks, I did check the spark arrestor and it's very clean.
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

Also, I checked the resistance from what I think is the secondary coil. i.e. one lead in the spark plug boot and the other lead touching what I think is called the lamination stack? Anyway that reading looks like it is 2.72k.
primerbulb120
Reply: Husqvarna 125b Won't Fire

primerbulb120

Spray starting fluid into the air intake and see if it starts. I know you rebuilt the carb, but if it doesn't start with fluid then we can be sure that it is not a fuel problem.

If you are getting spark, then it is not a problem with the flywheel. Check the spark plug gap (it should be 0.025 inch) to make sure you are getting enough spark.

Last of all, you measured the compression reading in lbs. Could you give me the reading in psi?
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

Thanks, primerbulb120

I've tried spraying starter fluid in numerous times and nothing. I should have said that earlier.

The compression should have said PSI. Sorry about that. Just checked it again and it's reading just over 100 PSI.

I've got what appears to be a new plug and it's definitely sparking. I'll check the gap and make sure it's 0.025 and report back.
primerbulb120
Reply: Husqvarna 125b Won't Fire

primerbulb120

Try taking the muffler off and see if it starts. Other parts of it might be clogged and keeping it from starting.
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

The plug is gapped to 0.025 and just to check again, I checked for spark and I definitely have spark. I sprayed starter fluid in again and nothing. I should take a video because I just can't believe this myself!
primerbulb120
Reply: Husqvarna 125b Won't Fire

primerbulb120

The only other thing I can think of is a clogged muffler. If you take the muffler off and it still won't start, then spray fluid through the spark plug hole instead of the air intake.
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

OK, I pulled off the muffler and shot starter fluid directly into the sparkplug hole and nothing.
roperdoug
Reply: Husqvarna 125b Won't Fire

roperdoug

You say the flywheel doesn't "appear to be spung". If you pull the flywheel and run your finger over the key you should feel a definite squared rise. Also look at the shaft. There is a slot the key on the flywheel goes into. Neither should be rounded. Put the flywheel back on with the magnet side away from the coil. See if you can turn the shaft with your hand while holding the flywheel in place. If it slips then the key is not holding it in place. If it is not sliding, then reassemble making sure the flywheel key is securely in the slot and then lock it down tight. I damaged my key when I didn't lock it down and it spun on me shearing the key.

Make sure the clip or connector on the spark plug wire is not broken or missing and that is snaps down tightly on the plug.

Another thing you can check is to make sure the muffler is clear. If it's clogged up then it's not letting the pressure off.

Have you or can you adjust the jets? What carb is on this? Try cranking it with the choke open and the throttle wide open and holding it open. If it fires then possible you are getting to much fuel to air mix and it's flooding. Remember it's not the fuel that burns but the vaporized fuel/air that burns.
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

My first thought was that It may be getting too much fuel. When you rebuilt it (fuel needle and metering lever side) did you Make sure the gasket goes on the carb body first, then the diaphragm with the little spoke in it. The spoke faces DOWN. With that metering diaphragm and gasket REMOVED on that side of the carb, attatch a piece of fuel line to the fuel inlet pipe and blow into it. You should hear NO air escaping thru the needle. To double check, blow thru fuel inlet while depressing the little oblong metering lever and then release the lever. You should get a HISS of air with it depressed, but not once you let it go. Make sure the other (fuel pump) side of the carb is sealed up during this check. If those 2 items were installed in the wrong order, then the diaphragm will hold the metering lever down and the fuel inlet needle valve will stay open. I think it may be getting too much fuel. Also, your Low and High speed mixture screws may need to be adjusted esp. if you have messed with them or taken them out to clean the carb.They MAY need to be removed completely and the low speed fuel circuit and high speed circuit cleaned. Use NO high psi compressed air as you can damage sensitive check valves. For the mixture screws, (If you can access them) From a lightly seated position (turned in), they both should be backed out about 1 1/4 to 1 1/2 turns. Check this stuff and report back. I feel it is a timing or fuel issue.
CHECKING THE COIL The legs on the coil module should be about .010-.012" away from the flywheel magnets. This is about the thickness of a standard business card. Use one for a gauge as steel feeler gauges do not work so well. I see this is a 28cc full crank engine with an external primer bulb; with lower crankcase fuel induction.
roperdoug
Reply: Husqvarna 125b Won't Fire

roperdoug

If you take out the two jet screws REMEMBER which one you took out where. The "L" idle screw is ALWAYS longer. There is a certain order for adjusting (link removed).
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

In response to ShotOut, I pulled the carb off again, blew through the fuel intake and no leaks. Pressed the needle valve lifter and I could hear it coming through the needle valve opening. Triple checked the order of the gaskets as I put them back on to make sure I had them correct. When I rebuilt the carb, I didn't touch the mixture screws.

I reset the coil to .011. Cleaned the plug, filled up the fuel and nothing.

There's a dealer here in the area that will charge me $25 to diagnose. I'll let you know what they say.

Thanks for your help.
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

Hi Meathead, Since this machine has the lower crankcase fuel induction, check and be sure that the "Pulse Hole" from the engine block thru small intake manifold (spacer) is clear. You may also have a "reed Valve" induction plate behind the carburetor manifold or spacer. Check it's condition as well. Many have screws holding them in place, some may not. Since you have GOOD compression, Good clean carb, GOOD air filter, and GOOD spark. about all that is left is Timing (Flywheel key-way inspection as Doug said) and lack of fuel entering the lower crankcase. If there is an air leak in the lower crankcase the vacuum needed to draw the fuel will be lost. The pulse hole is KEY here...as is the condition of the reed valve(s). Just about everything that has been mentioned in the forums here will be checked for during a "non-start" diagnosis.
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

OK, just got back from the shop. I handed it over and they wanted to know what I've done to this point. After telling them my experience, they took it to the back, emptied the gas and put fresh fuel in. The guy pulled on it until he was sweating like a horse and no fire. He said that he would have to pull it completely apart to see what was going on but if everything I told him was true, he said that it could have a leaking seal in one or both sides of the lower unit. If the lower unit is leaking, he said the thing will never fire.

He said the only way to diagnose that is to strip it down to the short block and do a leak-down test. He said they pressurize it to 6 psi and it has to hold for 20 seconds.

Does this sound viable? How exactly do I do this?

I brought it back home because this is something I want to try myself. I'm on a mission here. Either I'm going to get this running or I'm going give it the hee-ho across the fence into the neighbors yard. LOL
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

Meathead In my previous post I stated "If there is an air leak in the lower crankcase, the vacuum needed to draw the fuel will be lost." But to digress, your original post stated that the plug was wet with fuel.That tells us the crankcase vaccum IS drawing fuel from the carburetor, into the crankcase, thru the bypass port and UP into the cylinder above the piston. Fuel coming from the bottom of an engine like yours has to move thru a port (or channel if you will) in the cylinder wall. A bad air leak in the crankcase would prohibit that from occuring. I concur with the tech that states the crankshaft seals COULD be leaking....that is the case with any 2 stroke that won't start. They COULD be leaking. You stated it has run great for years. How OLD is this machine? Some machines reach old age and the seals STILL don't leak. I do not think there would be ANY fuel induction UP into the cylinder if leaking crankcase bearing seals were the culprit. Vacuum would be lost and the fuel would just collect in the bottom of the crankcase or carburetor throat.
So, yes, you can do a leak down test yourself or just a leak test. You can do an easy one or a more complicated one. The complicated one uses 2 gauges, one to measure psi going into the engine, and one to read the air pressure that is being held INSIDE the engine.You do NOT have to necessarily STRIP the machine to do this if you can easily access the spark plug hole, the fuel intake manifold, and the exhaust port.
Low pressure air (say @ 5 to 6psi) is pumped into the machine thru spark plug hole with the INTAKE and EXHAUST inlets and outlets sealed off. Then the static pressure remaining in the machine is measured. It makes it to the lower crankcase area (where the seals are) thru the piston ring gaps. All you really need is a cheap little air compressor, a coarse pipe fittting to thread into the spark plug hole... some type of tubing or air line from the compressor to fitting in the head and possibly some rubber and braces to seal off the Intake and exhaust inlet and outlet. People have used pieces of tire inner tubes to do this You can get by with one gauge really doing a basic leak test. The shop strips it down so they can SEE or HEAR the leak better, by spraying liquid around where the crankshaft EXITS the engine housing. Your machine probably has the pull start in the back or top and right behind your starter is the back end of the crank. With the starter removed, you may be able to see where it enters the block. The front of the machine may be more difficult to access with covers etc. in the way. Without checking, I am not sure the assembly there.
Anyway, the deal is to completely SEAL off the engine and pump air into it at low pressure and check to see if it escapes or stays inside the motor by seeing the leak or hearing it. That is it in a nutshell.
I still do not feel that crankcase seals leaking is the problem.
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

Meathead Please do NOT give your machine the heave ho. A unit like yours is worth fixing or at the very least...worth TRYING to fix. Look at it this way too. When all is said and done, think of ALL that you will have learned and be able to apply to any 2 stroke engine problems in the future! We are never so smart, we cannot learn something new. Good luck, have patience, and please post back!
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

OK, started pulling it apart and first thing I noticed when I got down to the seals, the seal under the flywheel was spotless. The seal on the other side was a mess. Caked up dirt and grease.



Before dissasembling any further, I tried to to a pressure test but was not successful between the pump, plugging all of the outlets and getting air into it so I kept going. Pulled the bottom off and the one seal is definitely damaged. One side looks like it got flattened somehow.

Next I pulled out the crank and the piston. The piston is pretty discolored.



Don't know if that's a big deal or not. I didn't see any major scoring on the piston or the cylinder wall.

So here are my questions:
1. Should I try to clean up the skirt of the piston and if so, how?
2. The piston ring is either stuck in the groove or it's designed that way. It is not free floating in the groove like I was expecting to see. How is it supposed to be?
3. If it is supposed to be free, what's the next step to free it?

Hope I'm on the right track.
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

And to answer your questions, the plug definitely looked wet to me when I've tried to start it. I've tried shooting starter fluid in there to get it to fire as well. Nothing

The machine is about 4 years old.
roperdoug
Reply: Husqvarna 125b Won't Fire

roperdoug

Strip it down to where you can pull the flywheel off. When you look at the flywheel on the side that faces the engine block. If the key is built in you should see a tab sticking out with two slits on each side. If the key is not built in you see about and eighth inch cut into the flywheel probably about an eighth inch deep. It you see two slits but there is no tab sticking out then it's been sheared. If you are not sure, put the flywheel back on with the fins facing outward, hold the shaft with your hand and turn the flywheel on the shaft while pressing down. You should feel it drop down and not turn any more. Hold the flywheel firmly with your hand and try to turn the shaft. If you can't then the flywheel is secured on the shaft. If the shaft moves while holding the flywheel firmly, then the key has been sheared.
You migh ask, why am I getting a spark if the key is sheared or the flywheel is spung. Depending on how the flywheel is locked in place, you could be tightening it where it turns with the shaft but not in the right place and still get a spark but the timing is off.
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

Meathead Clean up the skirt of the piston with strong solvent. The piston ring should turn in the groove and be free floating, not stuck. Use sovent or soak it altogether. Carbon is tough stuff. Rings are brittle. If you try to pry them loose, you greatly risk breaking them, so don't! Soak the whole works. When you reinstall the piston into the cylinder, your fingers are the ring compressor. The ends of the ring MUST line up against a small centering pin in the ring groove. You will not be able to see the pin until the groove is cleaned of carbon. The ring is NOT allowed to rotate while the engine is running, thus the need for the pin to hold it in place. You may have suffered an intermittent vacuum leak with the damaged seal. It should be replaced. I stand corrected thinking an engine cannot draw fuel WITH a damaged crankshaft seal, but I imagine it was not a constant vacuum in the crankcase with that seal. Clean it up good. Order a new seal. You'll be good to go after that.
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

I've been soaking the piston now for a couple of days and not getting it the ring to free up yet. I've tried carb cleaner, brake cleaner and the last is sea foam. What's next? Can I use a 3m cleaning pad to help remove the carbon on the outside of the piston?
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

You can use the pad, just dont scrub so hard that you scratch the sides of the piston a lot. After removing the carbon, you can repolish the piston walls using fine grade wet/dry paper. You are going to need to have patience with that ring. I have soaked carboned parts in used motor oil. The carbon will absorb the oil, softening it and allowing it to be removed. Try it. Gasoline soaking is an option too, although we know it evaporates. Has any of the carbon dissolved yet? Typically an item such as the end of a broke piston ring is used to clean the groove in the piston. If you remove it to clean, be careful as it is easily broken. Find the end gap on the ring, and using something small like a pick, pick there to give the solvent a place to get into the groove and UNDER the ring. Keep picking at the ring groove to get solvent flowing in there.
primerbulb120
Reply: Husqvarna 125b Won't Fire

primerbulb120

If it had 60psi of compression when you took it apart, I find it hard to believe that the piston ring is stuck. It would have more like 25psi in that case.
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

Well I'm not making it up. It's definitely stuck.
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

Mr. Bulb What if the ring is stuck in its' perfect running location? 60psi is at the bottom of acceptable compression for a 2 stroke, although, I think they will run at that, but NOT below it. Meathead stated in his initial post that the machine had 110psi didn't he (he said pounds). That would be PLENTY of compression. So, How is soaking the stubborn carboned up ring and piston coming along? Any progress Mr. Meathead?
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

Just took it out of the Sea Foam soak and it didn't dent it. Got it soaking in ATF fluid now while I'm waiting on my seal kit to arrive from ereplacement.
roperdoug
Reply: Husqvarna 125b Won't Fire

roperdoug

I can't see how you can get 110 psi if the ring(s) are seated in the landing. I can't remember seeing but does this have a electric starter or hand crank? How many times did you crank to get a reading. Getting the ring unseated out of the landing takes time. You can get a glass or container that the whole head will sit in and use SeaFoam (not the aerosol) and let is sit. Take it out and us the thinest feeler gauge you have and try and work it between the top and bottom of the ring and the landing. Be careful not to break or scratch the ring. You might be able to loosen it.
Are you using regular gasoline? Ethanol destroys these engines.
primerbulb120
Reply: Husqvarna 125b Won't Fire

primerbulb120

If I were you, I would replace the seal and not worry about the piston. Also, if it were that much trouble you could just pry the old one off and get a new one. A new one is only $4. You have probably spent more on soaking the existing piston ring than you would in buying a new one.
1240401
Reply: Husqvarna 125b Won't Fire

1240401

[QUOTE=ShotOut;84111]Mr. Bulb What if the ring is stuck in its' perfect running location? 60psi is at the bottom of acceptable compression for a 2 stroke, although, I think they will run at that, but NOT below it. Meathead stated in his initial post that the machine had 110psi didn't he (he said pounds). That would be PLENTY of compression. So, How is soaking the stubborn carboned up ring and piston coming along? Any progress Mr. Meathead?"
Sorry, but I had to get in here and clear this up. One of my hobbies is collecting/restoring chainsaws and your statement here is erroneous. The numbers you prescribe apply to a reed valve induction 2 stroke. This engine is piston ported, which is much fussier for blowby. 110PSI on this engine is probably minimal, it may run if you could get it to turn fast enough. You could spin it with a drill, which would spin it faster than the recoil, and it may start. Also, every compression tester is different, I have a Lisle and a Craftsman that never agree on the compression of an engine! In any case if the ring is stuck on a small "port blocked" engine it will never run right, if at all! Chances are you are having trouble getting the ring to unstick, it's because some of the aluminum has "moved" and is trapping the ring. A new ring is about $3.50 plus shipping, just get a new one and use a peice of the old ring as a "fit tester" to carefully wet-sand the edges of the ring groove until it fits correctly. On these single ring engines, you have no margin for error on ring fitment and compression loss.
Good luck
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

I stand corrected about the fuel intake system (no reed valve) as I misread the small drawings on this site and mistakenly thought the carburetor BOOT and carburetor PLATE were integrated with a reed valve induction plate. I have seen engines with reed valves that were piston ported. Poulan has a 32cc that is. I do not think the fuel induction system even enters into the equation as the intake port in a piston ported engine terminates in about the same place a conventional intake on an engine utilizing a side draft carb is located/.Yes, the engine is piston ported as it has the crankcase fuel induction ports in the cylinder. You, yourself just stated, that "It may start". Of course it will never run right with a stuck ring! But when testing, it just MAY produce compression. That is what shut it down in the first place most likely. What aluminum moved? From where to where? Carbon is holding the darn ring. If any aluminum moved, it was very little. He said he sees no scoring. Where is the aluminum that moved hiding ...in the ring groove? Inside the carbon under the ring?
I find on these single ring engines that the Ring end gap is really too wide with stock rings. There is a formula for computing WHAT it should be for optimum effect....it is not complicated, but tighter is better and means more compression. An engine this size should have a ring end gap of about .002". Check a normal small engine 2 stroke and you will find the gap is most likely 5 to 6 times that. I say let the OP do as he will, at least he WILL have learned something about his equipment.
primerbulb120
Reply: Husqvarna 125b Won't Fire

primerbulb120

Try to push the piston back into the cylinder with the ring on. If the ring sticks out too far for the piston to go into the cylinder, it ISN'T STUCK. Try compressing the ring with your fingers. I disagree about not getting any fire with a stuck piston ring. I have a FL1500 blower that had a stuck ring(from carbon deposits). 25 psi of compression. With starting fluid, the engine would pop and sputter even though the ring was stuck. In one of Meathead's earlier posts, he stated that the spark plug was wet with fuel. In that case there could be nothing wrong with the fuel supply. However, ShotOut said that it could be getting too much fuel. If that was happening, you could take the gas out and see if it worked with start fluid.

At this point I feel that it is no common problem, and even if you get rid of it you will have tried all the normal methods of getting it to run. If you get rid of it, give it to the local small engine dealer near you and see if they can fix it and sell it.
1240401
Reply: Husqvarna 125b Won't Fire

1240401

[QUOTE=ShotOut;84130]I have seen engines with reed valves that were piston ported. Poulan has a 32cc that is. I do not think the fuel induction system even enters into the equation as the intake port in a piston ported engine terminates in about the same place a conventional intake on an engine utilizing a side draft carb is located/.Yes, the engine is piston ported as it has the crankcase fuel induction ports in the cylinder. You, yourself just stated, that "It may start". Of course it will never run right with a stuck ring! But when testing, it just MAY produce compression. That is what shut it down in the first place most likely. "

At the risk of sounding antagonistic the induction method not only makes a difference, it is the key! What is a reed valve? Nothing more than a check valve right? What does a check valve do? It allows flow in only one direction. Perfect for the intake of a 2 stroke engine, as the last thing you want is air moving out of the crankcase through the carburetor! In this case, as the piston moves upward and the compression/intake stroke are initiated, the reeds allow intake flow as soon as atmospheric pressure exceeds the pressure in the crankcase. The intake cycle will continue until either TDC or the point where blow-by equalizes the pressure inside and outside the crankcase. If the compression loss causes an increase in crankcase pressure above atmospheric pressure, that differential is stored in the crankcase and only adds to the intake charge pressure within the case due to the one way nature of the reeds. You diminish the intake charge cycle time and effectively lean the mix with blow-by, but in a very constant way that simply limits your intake duration, not ideal but can be compensated for by simple carb adjustments.

Conversely with a "port blocked" or "piston ported" engine, IE and engine with no reed valves, the skirt of the piston blocks the port leading from the carb to the crankcase. As the intake/compression cycle is initiated, the crankcase pressure drops below atmospheric pressure as compression builds. Not until the skirt clears the intake port will the crankcase pressure equalize with atmospheric and draw in an intake charge. By this time some compression has already been built. The vacuum in the case and the compression in the cylinder accelerate blow-by and diminish the pressure differential when the port is opened, decreasing intake charge velocity and volume. After the port opens and the pressure equalizes, if the blow-by causes the crankcase pressure to elevate above atmospheric pressure, this will cause the crankcase to begin to "breathe" out of the carburetor as there is nothing to stop the flow. And any excessive case pressure before the port is covered by the skirt after detonation will flow out of the carb which if nothing else will create a backwards flow that must be counteracted before the next intake charge can enter. This also pollutes case for the next intake charge.
The summary is that non-reed engines are significantly more dependent on minimal compression loss.
OTOH I completely agree with you that ring end-gap on most single-ring engines is significantly beyond optimal.

And as for the OP, I'm all for him fixing this himself! In fact, I have very little faith in most small engine shops and strongly encourage people to learn to repair their small equipment themselves. I have at least a half dozen chainsaws that were "junk" according to reputable shops. The honest truth is that there isn't enough profit in small engine repair to warrant much troubleshooting. Especially on a piece of equipment that costs less than $200 new in most cases. And I also want the OP to learn something from this project, I'd just prefer that what he learns is accurate.
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

Not antagonistic at all. Good technical information. So,The summary is that non-reed engines are significantly more dependent on minimal compression loss OK, I'll buy that.....MEATHEAD....are you still with us??...Maybe he should have done what Primer Bulb said and just broke the old one off and cleaned the piston and installed a new one. NOT everyone has money for parts though, esp, nowadays. Give us an update Mr. Meathead....
BSmitty
Reply: Husqvarna 125b Won't Fire

BSmitty

[QUOTE=ShotOut;84166]So,The summary is that non-reed engines are significantly more dependent on minimal compression loss OK, I'll buy that...."
Exactly!! As far as the broken ring goes, maybe a Ketone of some sort (Acetone or MEK) would work to dissolve what gasoline would not? I like the idea of used motor oil as you stated earlier, the acidic combustion byproducts might work as a solvent as well as the residual detergents. I'm curious to see if he's made any headway on loosening the ring.

FWIW for some reason all of the sudden my username switched from 1240401 to BSmitty, not sure why that is, I had chosen my name before my previous post...
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

First of all, referring to me as "Mr. Meathead" makes me laugh! I just feel like a meathead when dealing with this. I know just enough about mechanical stuff to be dangerous and break things to the point of no return...

I could have scrapped this thing a long time ago and that probably would have been a smarter thing to do but I really want to figure out what's going on with this. I've never been so stumped with a small motor like this. It's just usually not this complicated even for me.

Anyway, soaking it in ATF seemed to do the trick. I was able to get the ring off but I got a little excited and ended up breaking it anyway. But that's OK because I had already ordered a new one after reading your suggestion. I could have gone and bought it from a local store but I've been buying through ereplacement because this forum and you guys have been so helpful. Glad to give ereplacement the business for what it's worth. Plus this has been a huge education for me!

So at this point, I'm just waiting for delivery. I'll keep you posted.
primerbulb120
Reply: Husqvarna 125b Won't Fire

primerbulb120

[QUOTE=BSmitty;84197]Exactly!! As far as the broken ring goes, maybe a Ketone of some sort (Acetone or MEK) would work to dissolve what gasoline would not? I like the idea of used motor oil as you stated earlier, the acidic combustion byproducts might work as a solvent as well as the residual detergents. I'm curious to see if he's made any headway on loosening the ring.

FWIW for some reason all of the sudden my username switched from 1240401 to BSmitty, not sure why that is, I had chosen my name before my previous post..."

The "1240401" username was created because that is what member number you are.
BSmitty
Reply: Husqvarna 125b Won't Fire

BSmitty

Cool, glad you got the ring out of the groove. Since it's already broken, I would work your way around the ring groove and make sure you can get a fragment of the ring to fit fully into the groove. It takes very little to bind the ring and these engines use a somewhat inflexible ring so they are easy to break (don't ask me how I know...). I'm sure a new, free ring will solve your problems.

Good to know about the member number, it's just a little strange to me that my older post kept my older name. In any case, we're good to go now!

His experience reminds me of a single ring Poulan 2050 saw I had. Refused to restart after fueling one day, after pulling on it till I was utterly frustrated I took a compression reading and read 95 psi. I took the recoil off and spun the motor with a drill and eventually got it to run for a couple minutes. It died again and I took another reading, and pulled 75 psi. Turns out my air filter was breached and I got a case full of wood chips! As I tried to run it the chips were working their way out of the case but the abrasion destroyed the ring (although it looked good). $5 for a new ring and I was back in business. Interestingly I only had 135 psi with the new ring running strong...
primerbulb120
Reply: Husqvarna 125b Won't Fire

primerbulb120

I have a Weed Eater FL1500 that has two piston rings. Is one of them a backup? That would seem uncommon with only 18 cc.
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

Mr. Meathead I, personally am glad you are enjoying your time and the banter on here; as I am too. What is also great is that you have learned. None of us are or will ever be too old to do that! Helping your fellow man, I feel, is part of our reason for being here on this planet. I remember "Meathead" from the TV Series All In The Family I think it was called. Edith, Archie and that blonde!
Glad for the update. If you replace the ring and the crank seal, you should be good to go. Sounds like you're well on your way. Let us know!
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

Hi there Mr. Bulb, I was told that the "second ring" on a small 2 stroke engine such as yours acts as a stabilizer to keep the piston skirt aligned in the cylinder. Evidently, somewhere along the way, engine designers noticed that the lower part of the piston was gyrating in the cylinder, wearing down the edges on the skirt and wearing the cylinder as well. Of course, this gyration was to a very small degree, but enough to warrant stabilization of the lower piston...helping to alleviate unwarranted wear and tear.
primerbulb120
Reply: Husqvarna 125b Won't Fire

primerbulb120

Actually, this is an older engine. How come most engines do not have this?
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

OK, got my gasket kit and they included a fairly heavy O ring in the kit. I can't figure out where that goes. Any idea?

http://www.ereplacementparts.com/gasket-p-1601557.html
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

Meathead Your gasket kit is a fit for 11 different machines. It is all inclusive in that regard. In the diagrams for YOUR machine, I didn't see the O-Ring in question, but one or more of the other 10 compatible machines may use it.
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

I feel that the engine designers sometimes go with 2 Rings as an optional feature on their engines, based on what tests have shown, user input, and possibly piston size.
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

Put it all back together and it fired immediately! Runs awesome! According to my compression guage, it is now reading over 140. I don't know if I have a crappy guage or not but that's what it's reading.

Once again thank you for all of your help and encouragement!
primerbulb120
Reply: Husqvarna 125b Won't Fire

primerbulb120

Good job getting it running!! I still can't figure out why you couldn't start it with starting fluid.
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

Bulb....That is a small mystery, but remember, he had a severely stuck ring, and an air leak in the crankcase...under those 2 conditions...even though it HAD compression...it made the fuel mixture too lean I guess, thus no fire.
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

MEATHEAD You did very well. Great to hear a happy ending! Now you can work on ALL your friends' stuff too right!! LOL

I was more than happy to TRY and help you and encourage you. Believe it or not, in some other forums, giving encouragement to a poster with a mechanical problem IS NOT considered to be any help..and the jackass that feels that way is a guy from Oregon named Bill Kaupan...I don't LIKE jackasses and I dont care for him.....you gotta know you did very well...and we are all glad...NOW you can go help the other guy on here with a Husqvarna backpack blower doing the SAME thing...he posted a few days back. GOOD JOB!
Meathead
Reply: Husqvarna 125b Won't Fire

Meathead

The encouragement from ShotOut is what made the difference for me. At that point, I was done and ready to buy a new one but ShotOut said to stick with it. Thanks again.

One more quick question, another guy who I think is also very knowledgeable with small motors told me that a stuck ring is very common on small motors when using cheap oil. If this is true, what oil should I be using?
ShotOut
Reply: Husqvarna 125b Won't Fire

ShotOut

Meathead: Thank you too! I feel I have received just about the highest compliment one can when helping someone...that is what makes it all worthwhile; esp. for me! Ahhh, the great oil debate. Depending upon who or whom you speak to, you will receive different answers. The practice of staying away from the cheap oil is good advice, no doubt about that. That being said, the cheapest oil you should use is a "synthetic blend" as it has the best of all the 2 stroke worlds in it. Many of them actually have fuel stabilizers in them also. The full synthetic oil is a good choice too. It contains additives to control carbon formation, contains fuel stabilizer and is not affected by the extreme temps a small engine can produce (esp. in HOT weather). So in summary; I suggest using at the very least a name brand oil that says "synthetic blend" or a full synthetic. As in 4 stroke oil, Full synthetic can contribute greatly to reducing any additional WEAR on the moving parts of the engine...bearings, rings, piston etc.
BSmitty
Reply: Husqvarna 125b Won't Fire

BSmitty

Very nicely done, congratulations! I'll agree with ShotOut on the oil debate. For the cost, it could probably be debated either way for synthetic but IMO quality is worth a few dollars. I hope my posts didn't get anyone too excited either, I can be a bit of a small engine nerd! I agree with ShotOut also that you did very well! Most people would have given up, but in the end you prevailed over a small cube 2 stroke. And IMO if you can make a < 40cc engine run you can make most anything run!! Again, well done!!!
primerbulb120
Reply: Husqvarna 125b Won't Fire

primerbulb120

As for oil, I use Echo PowerBlend synthetic because it was given to me along with a wrecked Echo edger.
zeusboy
Question: Husqvarna 125BT Blower Problem

zeusboy

Hi all, newbie here but was referred here by a friend.

I have a Husqvarna 125BT leaf blower that seems to lose power after running for about 5 - 10 minutes. It runs fine at first, but then loses power down to about half speed, running with inconsistent power. I had thought it may be with the carburetor, so I went in that direction and watched a Youtube video of how to take it apart and clean it, which I did. But, the problem still exists.:mad: If I then turn it off and let it rest for 15 minutes or more, it starts back up fine, but then goes through the same process all over again.

Does anyone think this may still be carburetor related or does anyone have any other ideas? Any suggestions would be greatly appreciated; thanks.
MRT
Question: Husqvarna Leaf Blower

MRT

Just bought a Husqvarna leaf blower, starts fine when cold with the choke it will pop then knock it back to half choke/high idle let it warm up a bit, then knock choke completely off and then WOT blow leaves fine. So the thing is still warm so I yank the cord it starts go to WOT and won't spool up runs for a minute bogs and dies. Went to tweak the carb no screws. Just 2 little knobs that have a kind of a knerl on them. Is there a special screw driver for these ajustments? Carb is made by Zama

Thanks
fancyboxy