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Stihl FS80 Trimmer.
When the starter rope is pulled it spins freely. Upon inspection I noticed the pawl and carrier were damaged. The nut in the middle was separated from the rest of the cup.
So i replaced the whole assembly and after 1 session of use the same thing happened. Clutch carrier broken once again.

What is causing this issue?

Hi, did you notice any vibration when using the machine after installing the new part?, was it a genuine Stihl part?, how tight was it done up?, check the crankshaft for lihear movement by pulling it in-out, check clutch on the other end of the crankshaft, check starter rope rotor for damage.

066 said:

Hi, did you notice any vibration when using the machine after installing the new part?, was it a genuine Stihl part?, how tight was it done up?, check the crankshaft for lihear movement by pulling it in-out, check clutch on the other end of the crankshaft, check starter rope rotor for damage.

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Genuine part, tightened snugly and no damage to starter rotor.
Didnt feel any unusual vibration during use, I just noticed the head beggan to spin slower than it ought to and then the engine stopped. Next thing I know....same problem again.
I'm wondering...could the bearings inside be at fault?

Broke yet another one of these starter cups. (#1 in diagram) The clutch looks just fine to me, but now I notice the starter rope rotor has damage most likely caused by this whole mess. (#8 in diagram) - I'll replace that.
According to the diagrams I've got everything installed correctly and now I'm beginning to wonder if there's a problem with the gearbox down in the trimmer head.

What do you guys think?

"snuggly" tightened sound good, but is there a torque callout?

motoman said:

"snuggly" tightened sound good, but is there a torque callout?

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I dont have specific torque numbers for that.

'bandit,, I do not know your exact application , but fasteners can break from over tightening and under tightening where metal fatique can occur from repeated cycles of bending and impact. If that bolt (bolts?) is either metric (8.6, 9 etc) or SAE 2 to six head bolt slash marks, look up the expected torque by the size/grade of the bolt shank either in this forum (archive search for chart) or just a few google pages will do it. If you lubricate be sure to reduce the torque callout.

This trimmer I've had for many years, never ever had a problem with it. Then all of a sudden this cup breaks....so I figure time just got the better of it.
Install a new one and it breaks after one use? Somethings definitely wrong here.....I dont think this issue is from thhe part being fatigued.