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Stihl KM55R (KombiMotor) shaft issue

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Liazard

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Discussion starter · #1 ·
My Stihl KM55R (KombiMotor) is starting and revving fine, but the shaft doesn't turn with the motor, like the shaft is disconnected. I'm talking about the part that engages and drives attachment tools like string trimmer and edger.

What should I be checking?

It's occurred to me to remove the engine cover to look at the shaft but last time I removed the top cover the entire trigger mechanism disassembled itself. Had to go to the shop to get it put back together. Should I be able to remove the cover to examine the shaft without messing up the trigger? Clues on how would be appreciated.

Thanks for any help.
 
#2 ·
Several posts/threads about yer shaft issues have been posted on here. Search.
Could be a problem with the clutch not engaging. Sometimes the two shoes get frozen to the pivot bolts. That's been covered here also.

As fer the handle/throttle assy., there should be two recessed torx screws on the side of the plastic grip. Loosen them and the grip/throttle assy will slide along/off the tube. They're two band type clamps. Don't have to mess with all the small screws that hold the two halves together.
Pretty sure that is in yer owners manual, as an adjustment.
 
#3 ·
Sounds like the motor isn’t on the drive tube all the way
 
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#5 ·
Sometimes when your sliding the motor onto the drive tube and the drive shaft isn’t lined up it will fill like the motor is bottomed out on the tube. Loosen the screws that clamp the motor to the tube. Use a crescent wrench on the opposite end of the drive shaft. Turn it till the shaft lines up and it should slide on another 3/4” or so. If your in when you turn the crescent wrench you should see the outer part of the clutch spin. Hope that helps.
 
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Discussion starter · #6 · (Edited)
I'm hoping the repair shop missed that when they reassembled the trigger for me. If I can I want to give it a try myself because I don't want to wait their standard 2 weeks. Will let you know. I think you're saying to turn the shaft from the far end where it connects to tools, right? It's round with the 2 little wire connectors.
 
#7 ·
Liazard said:
I agree and will take a look today.

BTW the only recessed Torx screws i see are at the bottom of the grip not the sides. I assume those are the screws for the band clamps.
Click to expand...
Yer probably right.
I was thinking it would be the same as the trimmers. My bad.
Mayhaps Dr. Jeff will save the day fer ya.
 
#8 ·
.........

Image
 
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Discussion starter · #9 ·
No luck. The Torx screws hold the outer sheath of the shaft, right? And I should be able to pull it back to view the shaft itself?

Just in case it matters the end of the shaft where attachments go on is round, not hex, on kombis.
 
#10 ·
Post a pic of the screws your talking about. And yes the very tip is round. About 1/4”. Then it is square
 
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#11 ·
Has it been working correctly at all since it was "repaired" by the shop or did it just stop working?

The top engine cover does not need to be removed in order to remove the upper tube with driveshaft. The only reason to remove the top cover in this case was if you had a clutch issue, a clutch drum issue or the end of the drive cable broke off in the drum.

The drive tube is secured between the upper/lower housing with 4 screws. However, between the rear two screws is another screw which lines up the tube and keeps it from rotating in the housing. Note, this screw is a shorter screw then the others! (See attachment)

You can also leave the tube in place and remove the clamp on the lower end and pull the driver out to access the driveshaft. Make sure neither end of the flex cable is rounded off or broken. (See attachment)

When tightening ANY of the screws just tighten until seated and a touch more by hand.
 

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Discussion starter · #13 ·
Took the handle apart trying to get at the muffler because of acceleration issues. Other than that, tools were engaging correctly. Took to shop for trigger issue, just couldn't get the springs to stay in place. First start after I got it back, starts and accellerates great (I had removed the arrestor screen) but shaft doesn't turn. They fixed the trigger but may have left something disconnected.

Will send photos tonight. Thanks for your interest!
 
#14 ·
Liazard said:
Took the handle apart trying to get at the muffler because of acceleration issues. Other than that, tools were engaging correctly. Took to shop for trigger issue, just couldn't get the springs to stay in place. First start after I got it back, starts and accellerates great (I had removed the arrestor screen) but shaft doesn't turn. They fixed the trigger but may have left something disconnected.

Will send photos tonight. Thanks for your interest!
Click to expand...
Ahh, ok

Then in that case, make sure the tube is seated against the rear of the engine housing and the small screw (between the 2 rear ones) is going into the hole in the tube. May have end of tube up against screw instead which would allow cable to "float" too far out of clutch drum.

Also make sure the clamp is fully installed onto lower end of tube so the driver didn't back out of the tube.
 
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#20 ·
Jeff in AL said:
Care to mention who this was directed at chief?
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That was directed towards big fishy.

Missing drive shaft, yeah, that could defiantly cause the problem
 
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Jeff in AL
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