Stihl FS38 throttle spring replacement - Stihl Garden

Question edited for clarity, and add MAKER, took me ages to work out what 'adjust the cab' was!
Question moved to make model category.

Information and videos in the link

https://www.google.com/search?q=stihl+fs38+weed+eater+carburetor+adjustment

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To replace the throttle on a Stihl FS38 weed eater, you'll need to follow these steps:

1. Disconnect the spark plug wire to prevent accidental starting.
2. Locate the throttle cable where it connects to the carburetor and carburetor housing.
3. Use pliers to loosen the lock nut on the carburetor side of the throttle cable and slide the cable out of the carburetor and carburetor housing.
4. Replace the throttle cable with the new one, feeding it through the carburetor and carburetor housing and tightening the lock nut on the carburetor side with pliers.
5. Check the operation of the throttle by starting the engine and confirming that the throttle cable moves freely and the engine speed changes accordingly when the throttle is manipulated.
6. Reconnect the spark plug wire.

It's recommended to consult your FS38's user manual for specific instructions as the process may vary slightly based on the model.

Question edited for clarity - maker name. No idea what you mean by a 'cruses shaft'. FULL 'make model (what is is)' in all questions please.

Here is one versus the other. I would think shaft swapping was fine.

https://www.google.com/search?q=Stihl+fs38+v+stihl+fs45

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https://www.stihlusa.com/WebContent/CMSFileLibrary/InstructionManuals/STIHL-FS-38-Owners-Instruction-Manual.pdf

No "gear box" on a curved shaft trimmer. Please peruse the diagrams at following link.

https://www.diyspareparts.com/parts/stihl/diagrams/fs38-z-2-mix/

You want to remove what?

here is a link. You can look on line by typing: parts list for a fs/38 stihl weed trimmer into browser. Took about 5 seconds to find answer.

https://www.diyspareparts.com/parts/stihl/diagrams/fs38-z-2-mix/

inside the muffler there is a screen that gets all gummed up, take muffler assy. apart and clean screen, if you have a propane torch, this works well as you burn crud off it becomes ash and wipes or blows off. first link shows how.
press the helpful button and follow me on fixya

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Heres the illustrated parts diagram showing the beakdown on the handle and location of the trigger mechanism. If you want the full parts manual, i can send it to you. :)

I googled your fs38. It is a Stihl FS38. The first sight on the search comes up with an 82 page operating manual from stihl.ca
This should help.
Good Day.

Look to see which one has a worn spot . That is the one I would use. If it isnt that one, try the other. Good luck...Lee