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nbuzz
05-14-2009, 12:39 PM
Hey guys, wondering if you can give me some advice.

I bought a new hedger last fall, Stihl HS 81 T. I've had nothing but problems with this unit. took it back to the dealership 3 times!!! every time it came back it worked better than before. but now its doing it again

Here's the issues:

1. hard starting when cold
2. won't rev up until its run for 5-10 mins
3. won't re-start after fuel fill up (motor still warm)
4. dies out on certain angles regularly
5. won't stay revved, bogs down (not on a load either)

The dealer claims he has cleaned and adjusted the carb. also said the fuel pick-up came unhooked, said that was fixed. I've never had a problem with these guys, they're my fav dealer. BUT I can't wait a week right now to have the fixed!! so %^&* frustrating.:help:

any ideas on how to fix it?? or should I suck it up and take it in again:hammerhead:

sry for the long post... thanx guys

Yuanding
05-18-2009, 09:30 PM
Hey guys, wondering if you can give me some advice.

I bought a new hedger last fall, Stihl HS 81 T. I've had nothing but problems with this unit. took it back to the dealership 3 times!!! every time it came back it worked better than before. but now its doing it again

Here's the issues:

1. hard starting when cold
2. won't rev up until its run for 5-10 mins
3. won't re-start after fuel fill up (motor still warm)
4. dies out on certain angles regularly
5. won't stay revved, bogs down (not on a load either)

The dealer claims he has cleaned and adjusted the carb. also said the fuel pick-up came unhooked, said that was fixed. I've never had a problem with these guys, they're my fav dealer. BUT I can't wait a week right now to have the fixed!! so %^&* frustrating.:help:

any ideas on how to fix it?? or should I suck it up and take it in again:hammerhead:

sry for the long post... thanx guys

I've had a different Stihl hedge trimmer for six years and it performed just like yours for the first six months i .e. like a pig. It seems they need a long break in period unfortunately, and in my experience they run better if revved to the max and used for an extended time, i.e. half an hour at a go. My hedgetrimmer has been used for hundreds of hours and runs loads better than when new.

Also, one of the biggest stumbling blocks with all two strokes is breathing. Make sure that air filter is scrupulously clean.

mowerknower
05-18-2009, 11:00 PM
check the fuel line again, if all they did was reinstall it there is a good chance it came off again, it needs to be clamped on the nipple

4.3mudder
05-18-2009, 11:51 PM
Hmm, won't restart after it is warm, sounds like a bad coil.

Bogs down at angles, sounds like the fuel line is not in the right spot.

It might be cold natured, I have a coulpe of things that do that.

nbuzz
05-19-2009, 12:14 AM
thanks for the info guys. that night I took them home and checked the fuel line.. it was connected. I had it running really well, I ended up adjusting the low end screw and it seemed like that was the problem. Ended up calling the dealer and letting them know about the problem, they said if I had any more issues with it to bring them in, so naturally they worked well friday and saturday.

took them out today to touch up some areas that a client wanted, and guess what same frickin problems!!

the air filter is spotless, clean fuel pickup, I've beening running 93 octane with the stihl premo oil to see if that would help... nothing seems to work.
the unit just decides when it wants to... wtf?

any ideas? before I just take them back... or do i try to have the dealer fix them again?

mowerknower
05-19-2009, 01:00 AM
Check the spark arrestor, for some reason the hs81 acts lean when the exhaust is plugged.

DT Lawn Care
05-19-2009, 01:23 AM
I had it running really well, I ended up adjusting the low end screw and it seemed like that was the problem.

I just got a Stihl Hedge Trimmer going for a neighbor, and all I had to do was adjust the high and low screws and now it's great! I did have to do it a couple of times though, so I wouldn't give up on it yet. GL

nbuzz
05-21-2009, 01:14 AM
thanks for the help guys!! really appreciate it. I had some time to tinker with it some more:hammerhead: can't really believe I'm stuck working on a brand new unit when my mowers with 900+ hrs. on them are running great. But anyways I checked the spark arrestor and it was spotless (as I expected, it has less than 40 hrs on it). I took it out anyways, no change in performance. played with the carb again, checked the fuel lines again. I dont see what the problem is... It ran Ok today, I mean I got the job done but I wanted to throw them in the water:cry:

so tomorrow I'm going to the dealer to see what can be done, but who knows.

mowerknower
05-21-2009, 01:40 AM
Yep, take it to the dealer, you have done what you can. Have them do a presure and vacuum test and determine what the problem is. If it has no leaks I would install a new carb.

4.3mudder
05-21-2009, 04:33 AM
ya, I would seriously take it back and demand another one. That one seems to be a lemon.

got2dv8
08-20-2010, 06:05 PM
I joined this site just because of the fact that during a Google search I was able to find useful information that ended up solving my dilemma. And I wanted to say thanks. I have a Stihl HS81 R and T. My R has always run like crap. Well finally it gave up the ghost and wouldn't run any longer... of course during a job. So firstly I got a carb rebuild kit, but that wasn't it. Then I swapped carbs on my machines, no dice. Next I swapped flywheels, pickup, plugs to no avail. Everything worked fine in my 81T. I threw in a new piston and rings but nothing. The strange thing was when I pulled the cord the sound was very muted compared to the 81T as it the muffler was obstructed. That's when I found this thread and read about the spark arrestor possibly being clogged. Pulled off the muffler (I can take these things apart in the dark by now) and took out the arrestor. Completely clogged! Couldn't even get compressed air through it. Cleaned it off but it was still buggered. Ripped of the mesh, stuck the threaded piece back on the muffler so it would bridge the gap to the pipe...pulled the cord and she came quickly to life.

Thanks a lot! After buying this thing for around $500 I really didn't want to have to trash it or put any more money into it.

Robert

The Lawn Ranger CT.
08-20-2010, 08:12 PM
I noticed the spark arrestors, in alot of the Stihl products become clogged if you don't run them wide open~!.... next time just unscrew the arrestor out and soak it in some carb cleaner over nite then hit it with a small wire bush shoud do the trick

rlitman
08-22-2010, 12:40 PM
Completely clogged! Couldn't even get compressed air through it. Cleaned it off but it was still buggered. Ripped of the mesh, stuck the threaded piece back on the muffler so it would bridge the gap to the pipe...pulled the cord and she came quickly to life.

That's an option, and soaking in cleaner before cleaning is another, but I would hit it with a propane torch for enough time to get it good and glowing (just a few seconds). After that, all the carbon should be gone.

dndodd
01-07-2012, 11:53 AM
My HS -81 is acting up after it gets hot it quits let it cool down for 5 minutes it will start up run for a short time then repeat.

The spark arrestor is clean(actually it is gone), new fuel filter, air cleaner is clean.

I suspect the coil anyway to test or any other suggestions?

ffemt1271
01-07-2012, 01:44 PM
I had shindaiwa ext hedge trimmer that ran like crap.sometimes and at certain angles and was hard to start.
Started troubleshooting it and fould the insulator.on the spark plug had come loose and would.slide down and cover the gap up and make it run like crap.
Posted via Mobile Device

dndodd
01-07-2012, 04:22 PM
I am suspecting something like that, thanks.

ffemt1271
01-10-2012, 06:35 PM
Did you get them running
Posted via Mobile Device

dndodd
01-10-2012, 06:53 PM
No haven't gone to get the new coil yet.

dndodd
02-08-2012, 06:24 PM
Did you get them running
Posted via Mobile Device

I think I finally fixed it. Bought a used coil over the Internet $25 versus $100 new. Didn't solve the problem.

Started playing with H and L screws, made it worse. Got them back to spec per the manual.

It was idling fine IMO but turning the the IDLE screw CC and increasing the Idle speed seemed to solve the problem. Simple as that.