Easy
15-30 minutes
Genuine Husqvarna replacement part, this part is sold individually.
The 503939601 Air Purge does just what the part name says.
It purges the air out of the carburetor.
Then it forces fuel from the fuel tank and fuel line in to the carburetor.
Air Purge 503936601
OEM part for: Husqvarna, Jonsered
Part Number: 503936601
$14.29
In Stock
Ships within 1 business day 
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Product Description ?
- Classification: Part
- Weight: 0.01 lbs.
- Also Known As: Purge Bulb, Plunger, Purge Bubble, Purger Bulb, Primer Bulb
- Shipping: Ships Worldwide
Frequently Purchased Together ?
Compatibility
This Air Purge will fit the following 645 machines. Confirm this part works with your model, and view the detailed model diagrams and repair help we have to offer.
Husqvarna
Jonsered
Show More Compatible ModelsThis item works with the following types of products:
- Chain Saw Parts
- Saw Parts
- Blower Parts
- Trimmer Parts
- Pole Saw Parts
- Edger Parts
- Hedge Trimmer Parts
- Pruner Parts
Customer Part Reviews ?
Average Rating (out of 5):
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5 stars
19
4 stars
1
3 stars
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2 stars
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Easy repair great fit
These air purges are the most frequent repairs I have on all my gasoline equipment. This one came quickly, fit well, was easy to put in, and has me up and running again.
Raymond -
September 29, 2023
Verified Purchase
Fixed
Perfect fit
Richard -
August 25, 2023
Verified Purchase
Chainsaw repair
Part came in on time and fit perfectly!
Guest -
June 12, 2023
Verified Purchase
Simple but essential
This part is simple but essential to priming and starting the tool. It has a limited three to four year lifespan, but replacement is easy, especially with the fast shipping, exact part and minimal cost.
Guest -
May 10, 2022
Verified Purchase
Easy, Fast Order, Perfect Part
Great and fast service. Part was perfect and easy to order.
Danny -
June 29, 2021
Verified Purchase
Air Purge
Arrived very fast and fit perfectly. My ice auger runs again.
Guest -
February 8, 2021
Verified Purchase
Just what was needed
The original primer bulb was cracked and made the saw impossible to start since it couldn't be primed. Getting to the bulb to replace it on a K760 gas saw takes a little bit of work. You have to pull off the top pieces and loosen the carburetor to get to the fuel lines with needle nose pliers. Once there the bulb pops right out and the new one snaps right in. Push on the fuel lines and re-bolt the pieces back on and you're done. A few pushes on the bulb to get the gas flowing and the saw started right up. Just what the saw needed to continue it's service life. A twenty dollar part and 45 minutes time saved a $900 saw.
Thomas -
November 6, 2020
Verified Purchase
Install was easy works great !
Weed eater starts and runs perfectly.
Guest -
October 13, 2020
Verified Purchase
Perfect match
Easy to replace once housing removed
Guest -
August 20, 2020
Verified Purchase
Works perfect.
Exact fit. Quick shipping.
Stephen -
August 17, 2020
Verified Purchase
Questions & Answers ?
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Customer Repair Instructions ?
All our customer repair instructions are solicited directly from other customers just like you who have purchased and replaced this exact part.
Air purge was cracked
dave - February 18, 2016
👍 31 of 32 people found this instruction helpful
Tool Type
Chain Saw
Difficulty
Easy
Time
15-30 minutes
Tools Used
Screwdriver, Pliers
Parts Used
Remove top cowl from saw --- remove air filter from carburetor --- disconnect fuel lines from purge with pliers --- remove damaged purge by pinching keeper tabs --- snap new purge in place --- connect fuel lines --- install air filter & cowl --- voila'
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Air purge cracked due to age.
David - August 16, 2017
👍 6 of 6 people found this instruction helpful
Tool Type
Trimmer
Difficulty
Easy
Time
Less than 15 minutes
Tools Used
Screwdriver, Allen wrench
Parts Used
Removed engine cover.
Used small screw driver to depress the tabs on air purge.
Pulled off both fuel lines from air purge, paying attention to which one connected where.
Attached fuel lines to new air purge and snapped it in place.
It was a very easy and straightforward repair.
Used small screw driver to depress the tabs on air purge.
Pulled off both fuel lines from air purge, paying attention to which one connected where.
Attached fuel lines to new air purge and snapped it in place.
It was a very easy and straightforward repair.
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Prime bulb return line dry rotted, leaking gas.
brandon - September 11, 2016
👍 6 of 6 people found this instruction helpful
Tool Type
Chain Saw
Difficulty
Hard
Time
1-2 hours
Tools Used
Screwdriver, Pliers, Nutdriver, Two picks, one straight, one 90 degrees, knife
1. Remove chain and bar( for easy maneuverability), empty gas in tank, then top cover, followed by handle and throttle grip. The throttle has to be disconnected from carb, and you have to spin the linkage to remove because it does not come straight out.
2. You can choose to remove carb, I was able to do repair without removing, probably more difficult, but might have saved a little time. I removed return line and fuel lines and prime bulb from saw, followed by grommets. To remove fuel line you have to open gas tank and pull out filter and fuel line with your 90 degree pick. Remove filter and hose, replace with new.
3. When I replaced grommets and hose, I put a little oil on them to make things go on a little easier. I found it is easier to install grommets on hose first and then install grommets on saw. You can always push and pull hose through.
4. Once all hoses are on and secure, reinstall your filter on line and replace inside tank. I cut about two inches off the tank line before installing filter, just because it seemed a little long, your choice. I only had one line that was bad, but I figured while I was replacing one, might as well do them all, the others are probably going to fail soon.
5. In order to replace exhaust screen, you will have to remove chain break handle, two hex head bolts, slide screen out, slide new one in and done.
6. Once installed, I reassembled everything in the reverse order it come out. Chain brake handle, main handle then throttle cover, remember to install throttle linkage, you have to spin it to get back next to the carb, this can be a little tedious, but make sure it is where it needs to go before bolting main handle on, or you have to take it apart again(my mistake).
7. After throttle cover, replace your top cover, and chain and bar, add gas and your good to go.
2. You can choose to remove carb, I was able to do repair without removing, probably more difficult, but might have saved a little time. I removed return line and fuel lines and prime bulb from saw, followed by grommets. To remove fuel line you have to open gas tank and pull out filter and fuel line with your 90 degree pick. Remove filter and hose, replace with new.
3. When I replaced grommets and hose, I put a little oil on them to make things go on a little easier. I found it is easier to install grommets on hose first and then install grommets on saw. You can always push and pull hose through.
4. Once all hoses are on and secure, reinstall your filter on line and replace inside tank. I cut about two inches off the tank line before installing filter, just because it seemed a little long, your choice. I only had one line that was bad, but I figured while I was replacing one, might as well do them all, the others are probably going to fail soon.
5. In order to replace exhaust screen, you will have to remove chain break handle, two hex head bolts, slide screen out, slide new one in and done.
6. Once installed, I reassembled everything in the reverse order it come out. Chain brake handle, main handle then throttle cover, remember to install throttle linkage, you have to spin it to get back next to the carb, this can be a little tedious, but make sure it is where it needs to go before bolting main handle on, or you have to take it apart again(my mistake).
7. After throttle cover, replace your top cover, and chain and bar, add gas and your good to go.
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Would not start cracked air purge bulb
Ted - February 25, 2017
👍 3 of 3 people found this instruction helpful
Tool Type
Trimmer
Difficulty
Easy
Time
15-30 minutes
Tools Used
, allen wrench
Parts Used
Removed rope starter mechanism to gain access to air purge.
Note the purge bulb is clocked so it will only seat in one direction.
reassembled.
Note the purge bulb is clocked so it will only seat in one direction.
reassembled.
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Leaking gas, and would not run for a full min.
william - June 30, 2016
👍 2 of 3 people found this instruction helpful
Tool Type
Trimmer
Difficulty
Medium
Time
30-60 minutes
Tools Used
Screwdriver, Socket set, Wrench Set
Parts Used
Pulled starter recoil
Pulled bottom plate
Removed gas tank
Removed fuel line and air purge line
Replaced purge bubble
Reinstalled all other parts
Pulled bottom plate
Removed gas tank
Removed fuel line and air purge line
Replaced purge bubble
Reinstalled all other parts
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Primer punctured
Michael - July 30, 2016
👍 1 of 1 people found this instruction helpful
Tool Type
Trimmer
Difficulty
Easy
Time
15-30 minutes
Tools Used
Screwdriver, Pliers
Parts Used
1. Removed screws for the frame
2. Pulled out old primer
3. Removed two fuel lines
4. Placed in the new primer and connected both fuel lines
5. Placed frame back on and screwed in.
2. Pulled out old primer
3. Removed two fuel lines
4. Placed in the new primer and connected both fuel lines
5. Placed frame back on and screwed in.
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Purge cracked would not prime, upon inspection throttle cable appeared severely frayed near the carb, after removing throttle cable, spring was found broken
Terry - April 2, 2016
👍 1 of 1 people found this instruction helpful
Tool Type
Trimmer
Difficulty
Medium
Time
30-60 minutes
Tools Used
Nutdriver, Star bit
The purge is fairly simple to replace, it's kinda like a snap tight. I broke the old one taking it off, which informed to be careful putting the new one in. I put a little lithium white on the two ears that snap it into place. That helped go in without me putting to much muscle on it. The throttle cable and spring was not so simple and requires a bit of patience. The main thing is pay close attention to how you take it apart. Everything has its place it just may take a moment to figure it out. I advise that if you need to replace the cable, buy the spring as well. Even if it's not broken that way you can leave it assembled till your parts come in and taking it apart is fresh on your mind.
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Air purge pump bulb hardened and split open
Robert - September 7, 2018
Tool Type
Trimmer
Difficulty
Medium
Time
15-30 minutes
Tools Used
Screwdriver, Pliers, Nutdriver
Parts Used
1. Removed to top casing to completely expose the air purge pump.
2. Disconnected the two fuel lines from the broken air purge pump.
3. Removed the air purge pump by depressing the snap in bottom with a flat edge screw driver.
4. Positioned the new air purge pump to align with the two fuel lines and made the connection.
5. Being careful not to disconnect the fuel lines, aligned the air purge pump with the snap in cut- outs and pushed into place.
6. Depressed the air purge pump to be sure it worked.
7. Re-installed the top assembly.
2. Disconnected the two fuel lines from the broken air purge pump.
3. Removed the air purge pump by depressing the snap in bottom with a flat edge screw driver.
4. Positioned the new air purge pump to align with the two fuel lines and made the connection.
5. Being careful not to disconnect the fuel lines, aligned the air purge pump with the snap in cut- outs and pushed into place.
6. Depressed the air purge pump to be sure it worked.
7. Re-installed the top assembly.
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fuel lines and air purge old and brittle ('09) Husqvarna 223L Trimmer
CHAD - August 22, 2018
Tool Type
Trimmer
Difficulty
Easy
Time
15-30 minutes
Tools Used
Pliers, Allen wrench
Removed starter assy housing ( 3allen screws ) just for easier accessability , removed top cover ( 1 allen screw ) - took picture of three fuel lines (routing) - simply removed and replaced all above items mentioned . RUNS GREAT ! Cheaper than buying a new trimmer !
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Drive shaft broke on one trimmer and air pump for fuel line leaked for other trimmer.
Michael - August 1, 2018
Tool Type
Trimmer
Difficulty
Medium
Time
15-30 minutes
Tools Used
Screwdriver, Pliers, Nutdriver, Allen wrenches
Air pump on Husquavarna:
1. Remove side cover and fuel lines from air pump.
2. With screwdriver, push in tab on rear of pump to release from frame.
3. Align new pump in frame and snap into place.
4. Use needle nose pliers to carefully attach fuel lines.
5. Press air pump bulb 3 or 4 times to check for leaks.
6. Reinstall side cover.
Drive shaft on Homelite:
1. Remove trimmer head assembly on end of shaft.
2. Remove safety guard from end of shaft.
3. Remove handle from shaft.
4. Remove throttle assembly from shaft noting how the linkage fits back in casing.
5. Remove clamp noting location.
6. Remove shaft assembly from engine.
7. Install new shaft and tighten clamp in same location as removed. You may need to turn end of the shaft so the new drive shaft slides into engine.
8. Install throttle assembly assuring throttle linkage works as you assemble.
9. Replace handle and safety guard on shaft.
10. Replace trimmer head.
1. Remove side cover and fuel lines from air pump.
2. With screwdriver, push in tab on rear of pump to release from frame.
3. Align new pump in frame and snap into place.
4. Use needle nose pliers to carefully attach fuel lines.
5. Press air pump bulb 3 or 4 times to check for leaks.
6. Reinstall side cover.
Drive shaft on Homelite:
1. Remove trimmer head assembly on end of shaft.
2. Remove safety guard from end of shaft.
3. Remove handle from shaft.
4. Remove throttle assembly from shaft noting how the linkage fits back in casing.
5. Remove clamp noting location.
6. Remove shaft assembly from engine.
7. Install new shaft and tighten clamp in same location as removed. You may need to turn end of the shaft so the new drive shaft slides into engine.
8. Install throttle assembly assuring throttle linkage works as you assemble.
9. Replace handle and safety guard on shaft.
10. Replace trimmer head.
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All our customer repair instructions are solicited directly from other customers just like you who have purchased and replaced this exact part. While we moderate these reviews for profanity, offensive language or personally identifiable information, these reviews are posted exactly as submitted and no alterations are made by our team.
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