Stihl HS46C - Blade Drive Issue

rjsdavis

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Hello to all

Newbie - so would deeply appreciate any assistance resolving this annoying issue, and thanks in advance for any responses.

I have an HS46C H/T. It has been fine for a long time and from new, and the engine starts and runs just fine. However, it has developed a drive issue. Mostly, the blades do not drive. Initially it felt like there was simply no connection between the engine and the blades, as it felt as though there was no "resistance" from the engine when given some throttle.

However, when I tried giving it full throttle for a few seconds, I noticed that the blades moved ever-so slightly (literally a mm or two). I tried it again, but this time shook the whole unit whilst it was running, and suddenly, the blades jumped into life and starting sliding at full pelt. Upon release of the throttle, they stopped and wouldn't restart drive without more reasonably vigorous shaking and they starting sliding again. Being aware that there was a problem to be solved, I cut the engine so as not to risk damaging it internally. It seems clear that something is "sticking" or not releasing internally that requires the shaking to help it to do so.

I have limited experience of working on these two stroke motors - does it seem likely that there is an issue with the clutch assembly with my H/T? Assuming so, I'm wondering if these clutch units can be serviced, or whether it should simply be replaced? The H/T has seen relatively limited use, and not in a commercial environment, so it has not had a hard life at all and is very, very clean as a machine. I took the bottom cover off to have a look - it's well greased, so I am little perplexed as to how any part of the mechanism has become a bit sticky, or stuck. Nothing is obviously broken that I can see.

If it's not likely to be the clutch that is causing this issue, can someone point me in the right direction as to what it is? My plan is to order whatever parts are necessary, and follow a YouTube video to replace/service whatever it is...

Many thanks!
 

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StarTech

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Hedger is fully serviceable but you will need some specialized tools. And the clutch drum is worn out you will need a torch and digital none contact thermometer to heat areas shown in the service manual to replace the bearing and the clutch drum to 250F.

For a novice this is not a project to attempted without supervision and/or the service manual.
 

rjsdavis

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Hedger is fully serviceable but you will need some specialized tools. And the clutch drum is worn out you will need a torch and digital none contact thermometer to heat areas shown in the service manual to replace the bearing and the clutch drum to 250F.

For a novice this is not a project to attempted without supervision and/or the service manual.

Hello StarTech

Thank you for taking the trouble to reply.

I know that the H/T is serviceable, which is why I've upgraded all my kit to Stihl. I want it to go on and on!

After reading your reply, I started looking on YT for a clutch/bearing replacement video. Found one for a 45. Is the 46C fundamentally different? After having watched this one, I couldn't quite see what special tools would be needed, and what the 250F heat is for? Your expert tutelage is most welcome!
 

StarTech

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The heat is for removal and installation of both the drum bearing and the clutch drum. It also takes a special tool along with a piston stop to remove the clutch itself.

Here is just a sample from the service manual on just the clutch drum replacement.
1655765531770.png
 

rjsdavis

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Jun 20, 2022
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The heat is for removal and installation of both the drum bearing and the clutch drum. It also takes a special tool along with a piston stop to remove the clutch itself.

Here is just a sample from the service manual on just the clutch drum replacement.
View attachment 61089
Thank you for this.

This shows a near identical disassembly of the clutch and bearing to the video I watched the other day, working on an HS45.
 
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