Stihl HS81 problems

I'd certainly avoid the so-called service Tom........ I always wonder what they actually do to justify £80 or so...... there is so little that needs doing....... I've never needed to change a fuel filter, still on the same plug after 3 years use, air filter just needs a blow out, if you've a 4-Mix (I know you haven't!!), the valves take 5 minutes. The main thing they do is sharpen the blades which can be done with an angle grinder in 30 minutes max........ they're onto a winner with this servicing lol. Regarding your clutch, again, there's very little to go wrong and if you can clean out the carb, the clutch is nothing....... if its not disengaging, the most common fault, one of the springs has probably broken. What's it on out of curiosity?

Tom Beevor said:

Hi everyone, thanks for the suggestions, I'm trying to avoid a service if I can help, it, but Roy, the HS81 isn't a 4-Mix, however, I do have a 4-Mix machine that happens to have clutch problems too! That one will have to go to my dealer...

Replies

Geoff Norfolk May 15, 2014 at 1:22pm

presume you mean the hs81t................. must be a carb problem. I'd strip it down and blow through all the airways etc with compressed air. Replace the diaphragms etc...... comes as a kit. If this has suddenly come on, it won't be the fuel filter
PRO

Darren Walters May 15, 2014 at 9:30pm

I'm not sure about the 81 but on my hs45 conifer and other small leaves build up underneath the air filter cover behind the foam pre-filter.

Might be worth a look.
Paul McNulty May 15, 2014 at 10:16pm

Sounds like it's in need of a service, when was it last given some TLC?

A full service on a 2-stroke machine might cost £80 including parts, but that's nothing when you consider how many hours it does in a year.
Craig Spence And Hedges May 15, 2014 at 10:17pm

i had the same problem and it was the petrol had gone off (was only 3 days old) worth looking at it
Neil Copeland May 16, 2014 at 7:14am

Mine did exactly the same. It needed a carb service which cured it. Got my local dealer to do it
Roy Bretton May 17, 2014 at 11:57am

I have used Stihl equipment for many years and used to find it very reliable, I have to say with these four mix engines, they don't seem to be very reliable, we seem to have a lot more problems with the engines than we used too! I don't know if the manufacturers are struggling with the omission levels, but I do understand that many users are having problems with these engines.

The Stihl hedge cutter that I use has very similar problems to what your hedge cutter has Tom!

I look forward to seeing more applies on the subject.
Paul McNulty May 17, 2014 at 12:02pm

You do need to have the 4-mix engines serviced more often, my guy does the carb, valves etc. in about an hour so it's not too bad a couple of times a year.
PRO

Seth Burgess May 17, 2014 at 4:07pm

4-mix engines will be unreliable if you use the red oil. They're supposed to run on super/ultra 2 stroke and not the standard oil.

According to my dealer Stihl are trying to make it work with red oil but are having trouble as the valve system is fiddly or something like that.
Geoff Norfolk May 17, 2014 at 4:56pm

I'd certainly avoid the so-called service Tom........ I always wonder what they actually do to justify £80 or so...... there is so little that needs doing....... I've never needed to change a fuel filter, still on the same plug after 3 years use, air filter just needs a blow out, if you've a 4-Mix (I know you haven't!!), the valves take 5 minutes. The main thing they do is sharpen the blades which can be done with an angle grinder in 30 minutes max........ they're onto a winner with this servicing lol. Regarding your clutch, again, there's very little to go wrong and if you can clean out the carb, the clutch is nothing....... if its not disengaging, the most common fault, one of the springs has probably broken. What's it on out of curiosity?

Tom Beevor said:
Hi everyone, thanks for the suggestions, I'm trying to avoid a service if I can help, it, but Roy, the HS81 isn't a 4-Mix, however, I do have a 4-Mix machine that happens to have clutch problems too! That one will have to go to my dealer...
Derek Conway May 17, 2014 at 5:29pm