Hs80 tuning advice

[Conner]

I have tried to search the forum but have drawn a blank. I recently acquired an HS 80 hedge trimmer. Looks to be in good condition. It’s not running very well. It either runs ok once started but dies at idle or won’t rev. There are only 2 adjusting screws. As in first pic. The case shows H/L for one and LA for the other. Can anyone help me with some base settings. I’ve tried 1-2 turns out on HL. Which will get it to start but the LA  doesn’t seam to do much. Just need a starting point. Thanks in advance. 

[swinny]

LA is your idle bud. 

 

HL your high and low fueling

[Conner]

Yes I understand that. I’ve set a few chainsaws up. Normally there is a separate hi and low. And a separate LA for the idle. Unsure how the high and low can be controlled by one screw. 

[Muddy42]

https://www.stihlusa.com/webcontent/cmsfilelibrary/instructionmanuals/hs75_80_manual.pdf
 

[Muddy42]

It doesnt have a H like a chainsaw just L and idle. The standard setting for L is open one turn, then adjust idle so the cutters dont move.

 

If you cant get to this stage quickly or the machine isnt idling, I’d start looking for air leaks.

Edited 11 hours ago by Muddy42

[Conner]

Thankyou il give that a go this morning. 

[tree-fancier123]

sometimes the diaphragm or other gubbins not working, if so try a copy carb off ebay, I have quite few machines running the copy carbs, sometimes a genuine carb on ebay at reasonable cost

Genuine Stihl HS72 HS74 HS75 HS76 HS80 HS85 Carburettor 4226 120 0600 /0602/0604 | eBay UK

WWW.EBAY.CO.UK

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HS80, HS85. Stihl Genuine Carburettor New unused. Carburettor C1Q-S28E. What you see is what you will receive x1 carburettor...

 

[Mark Bolam]

Probably worth a carb clean and check the diaphragm as TF says above.

[Conner]

Thank you il try the settings first then the carb. Suspet the diaphragm myself as when running it is hunting. Just needed a starting point.