Troybilt TB22 String Trimmer and the Flying Bump Knobs

unit91

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  • / Troybilt TB22 String Trimmer and the Flying Bump Knobs
I have bought 3 replacement bump knobs for this trimmer, and every one comes flying off after about 5-10 seconds of use. I securely tighten them by hand but they keep flying off. Help!
 

unit91

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  • / Troybilt TB22 String Trimmer and the Flying Bump Knobs
By "flying off" I mean they immediately come unscrewed and fall off. GOT TO BE A REASON!!!!!
 

bertsmobile1

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  • / Troybilt TB22 String Trimmer and the Flying Bump Knobs
What comes off, just the knob or the knob & the cover plate.
If it is just the knob that is pulling through the either the flange on the knob is too small or the hole in the cap is too big.

The the entire cap comes off then the tabs that hold it in have sprung.
Put it in some hot water for 15 minutes bend them out and hold them out till the cap / head cools down .
 

unit91

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  • / Troybilt TB22 String Trimmer and the Flying Bump Knobs
The small round knob that screws into the head (looks like a push mower gas cap). Has a bolt in the center that screws into the center of the head. Immediately unscrews when engine starts.
 

unit91

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  • / Troybilt TB22 String Trimmer and the Flying Bump Knobs
If I take the inner reel (the part that string wraps around) off and run trimmer with it off, the bump knob stays put. If I replace the inner reel, the bump knob unscrews itself and comes off. The bump knob screws in clockwise, the spool head spins counterclockwise when trimmer is running. With the inner reel removed there is no pressure from the spring against the bump knob which allows the bump knob to remain in place. With the inner reel in, the spring pushes the inner reel against the bump knob and keeps it from spinning with the rest of the assembly, thereby causing the bump knob to unscrew itself and fall off.

I know someone out there can solve this. Thanks.
 

bertsmobile1

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  • / Troybilt TB22 String Trimmer and the Flying Bump Knobs
We don't get that type of head down here sorry.
 

unit91

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  • / Troybilt TB22 String Trimmer and the Flying Bump Knobs
What's the phone # for troybilt support?
 

ILENGINE

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  • / Troybilt TB22 String Trimmer and the Flying Bump Knobs
Is it possible the inner or outer spool ratchet stops are worn or broken and allowing the inner spool to rotate the wrong direction when you increase or decrease the throttle and unscrew the bump knob.
 

unit91

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  • / Troybilt TB22 String Trimmer and the Flying Bump Knobs
Can you send a photo of what it should look like so I know what I'm looking for? Thanks.
 

ILENGINE

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  • / Troybilt TB22 String Trimmer and the Flying Bump Knobs
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