Husqvarna 455 Bogs Under Load

nygrappler

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My father inherited a barely used Husqvarna 455 from my uncle who passed away a few years back. Dad said it wouldn’t run right.

The tank was empty when I got it. I filled it with fresh fuel (50:1 non-ethanol mix with full synthetic 2 cycle oil), filled it with bar oil, ran the plug over my wire wheel, checked the gap, checked the air filter (looked brand new) and fired it up.
It runs great until you put a load on it (put it into some wood), and it bogs right down.

I pulled the carburetor out and sprayed it down with carb cleaner. Fired it up and it ran great for one tank of fuel. Refilled it with fuel and it started bogging again.

Do I pull the carb and spray it down again? I’m guessing my uncle had run ethanol fuel in it and let it sit. Any other suggestions? Thank you in advance.
 

Backstage

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Sounds like it’s running lean (causing overheating) and heat soaking? That happens if:
A - You can’t deliver enough fuel for the air volume delivered
B- It can sneak air it shouldn’t have (leak)

Fuel delivery side. A carb rebuild is not hard to do for anyone comfortable pulling the thing. Common issue, especially with modern gas, is varnishing throughout the carb, especially in that little filter screen in the pump (bottom on that carb). Easy not to completely clean that with the carb spray. You can remove it gently with a pointed tool, and reinstall with a pencil eraser.

Part number for the rebuild K1- WTEA. A Walbro 500-13-1 is a cheal tool that’s also helpful to set the new needle lever height.

While you’re at it, slice the plastic tabs that limit carb adjustment. Screw the EPA and their insistence that trashing a saw by running it lean helps the environment.

You may be need as simple an adjustment as turning the H screw out a 1/4 turn.
 

nygrappler

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Sounds like it’s running lean (causing overheating) and heat soaking? That happens if:
A - You can’t deliver enough fuel for the air volume delivered
B- It can sneak air it shouldn’t have (leak)

Fuel delivery side. A carb rebuild is not hard to do for anyone comfortable pulling the thing. Common issue, especially with modern gas, is varnishing throughout the carb, especially in that little filter screen in the pump (bottom on that carb). Easy not to completely clean that with the carb spray. You can remove it gently with a pointed tool, and reinstall with a pencil eraser.

Part number for the rebuild K1- WTEA. A Walbro 500-13-1 is a cheal tool that’s also helpful to set the new needle lever height.

While you’re at it, slice the plastic tabs that limit carb adjustment. Screw the EPA and their insistence that trashing a saw by running it lean helps the environment.

You may be need as simple an adjustment as turning the H screw out a 1/4 turn.
Thank you much for your detailed response.

I will start by pulling the carb again and checking the screen and spraying it down. While in there, I will pull the plastic tabs as recommended.

Second will be the rebuild kit.

Thank you!
 

nygrappler

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I would recommend waiting on pulling the cylinder open until you can diagnose that there’s a problem under it first.
That would be a first for me so definitely not jumping into that without ruling out the carb and fuel filter. I think it’s carb related as it ran great for one tank after having it apart. Carb is a pain to get out though. One bolt is 1/3 turn at a time and readjust the wrench. I’ll keep you posted. Thanks!
 

Backstage

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You need a long 4mm hex driver, ideally a T handle ACE Hardware sells them single. The two on the bottom of the carb are difficult to access. You can also drop the handle by removing the AV mounts.
 

nygrappler

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You need a long 4mm hex driver, ideally a T handle ACE Hardware sells them single. The two on the bottom of the carb are difficult to access. You can also drop the handle by removing the AV mounts.
I took it out without removing the handle…hence the 1/3 turn at a time. I’ll consider removing the handle. The other three I accessed easily with an extension. Thanks!
 
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