Air Purge 503936601

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'

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.

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.

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.

Pulled starter recoil
Pulled bottom plate
Removed gas tank
Removed fuel line and air purge line
Replaced purge bubble
Reinstalled all other parts

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.

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.

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.

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 !

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.