Stihl FS45, HS80 and HS45-z All Stalling under Acceleration

Guyph_01

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  • / Stihl FS45, HS80 and HS45-z All Stalling under Acceleration
Hi Guys,

I'm new here and this is my first post. A bit about me..., I like to play and tinker with any engines I can find, usually get them given from familly to fix or buy them not running, service them and get them running good and sell them and start over.

Anyway I have four Sthil machines that I can't get going and I have no idea why?? They all start and Idle fine but when you give them gas they bog down and stall. I have cleaned the flame screen in all of them, Carbs cleaned, worst ones I have put new carb kit in them, Also tried a cheap ebay carb replacement but always the same result, starts and runs fine but bogs down on throttle.

This happens with two FS45, A HS45-z and a HS80..

Using fresh fuel with all of them. Only cleaned the plugs.

What do you guys think? Or what should I be testing/ Looking for?

Thankyou
 

dfbroxy

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  • / Stihl FS45, HS80 and HS45-z All Stalling under Acceleration
Have you changed fuel filter and fuel lines? Did you replace gasket between carb and intake? Did you try adjusting the H adjustment screw on the carb. If you have never done this then look it up on utube and be careful because if done wrong can blow up engine.
 

bertsmobile1

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  • / Stihl FS45, HS80 and HS45-z All Stalling under Acceleration
The low speed jet is adjusted wrong and most likely the throttle stop as well.

You need to decide if they are dieing from being too rich or too lean then adjust the low speed needle accordingly.

You should start by adjusting the high speed needle just slightly rich then after that do the low.
If the main jet is clean then you should be able to start a hot engine with the throttle wide open.
Take heed of what dfbroxy posted because the difference between runs like a pearler and wizz BANG ; scrap metal can be as little as 1/2 turn on a needle.

Initial settings are
FS 45; L-1 , H-0.75
HS 45; L-1 , H-0.75
HS 80; L-1 , H-0.75

If they do not start on those setting then something is very wrong
 

Guyph_01

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  • / Stihl FS45, HS80 and HS45-z All Stalling under Acceleration
The low speed jet is adjusted wrong and most likely the throttle stop as well.

You need to decide if they are dieing from being too rich or too lean then adjust the low speed needle accordingly.

You should start by adjusting the high speed needle just slightly rich then after that do the low.
If the main jet is clean then you should be able to start a hot engine with the throttle wide open.
Take heed of what dfbroxy posted because the difference between runs like a pearler and wizz BANG ; scrap metal can be as little as 1/2 turn on a needle.

Initial settings are
FS 45; L-1 , H-0.75
HS 45; L-1 , H-0.75
HS 80; L-1 , H-0.75

If they do not start on those setting then something is very wrong

So I had a little play with the settings you recommended. They still do the same thing. They all start and run fine on idle but as soon as you accelerate they bog down and stall.
Also the HS80 doesn't have a H needle on the carb.
 

bertsmobile1

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  • / Stihl FS45, HS80 and HS45-z All Stalling under Acceleration
So I had a little play with the settings you recommended. They still do the same thing. They all start and run fine on idle but as soon as you accelerate they bog down and stall.
Also the HS80 doesn't have a H needle on the carb.

1) they are not my settings they are Stihl's initial settings.
You start from there .

Set the high speed jet to maximum speed then screw the needle slightly out ( rich ).

To do that you hold the throttle wide open , screw the H jet in till the engine starts to miss
Then screw the needle out till it starts to miss, then screw it back to the 1/2 way point between these two + about 1/8 turn.
The high is then set.
Having just done this you will now know the different sounds of lean running & rich running.
So when you start to throttle on listen to what the engine is telling you and screw the L needle in the appropriate direction, then adjust the throttle stop so the tool just stops turning.

As for the 80 it obviously has a new EPA compliant non adjustable carb.
There will be a H needle but it is most likely got epoxy over the top so you can not meddle with it.

Two options with that one
But the best is to toss it & get a new carb
 

Guyph_01

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  • / Stihl FS45, HS80 and HS45-z All Stalling under Acceleration
Ok, How good are the ebay carbs from China? Here in Australia genuine carbs are quite expensive!

Not sure if i can tune the others as you described. As, as soon as i touch the throttle the engine wants to stall. If i hold it wide open it stops! All 4 machines are doing the same thing!

Thx
 

bertsmobile1

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  • / Stihl FS45, HS80 and HS45-z All Stalling under Acceleration
Gripskies, Jackmax & Allpower ( now in Liqudation ) all wholesale good quality aftermarket carbs from reliable sources.
Off ebay you take your chances.
Lots of garbage that fails the quality control in China ends up on Ebay, usually via Hong Kong.

IF the part has no brand name treat it as pot luck.
Then again we Australians are renown for being the stupidist gamblers on the planet so go fr the cheapest one and buy some lotto tickets while you are at it.
 

upupandaway

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  • / Stihl FS45, HS80 and HS45-z All Stalling under Acceleration
Ok, How good are the ebay carbs from China?.....
Thx

As a hobbyist myself, i have bought and am ok with carbs from HK. So far 8??for8 and they all run fine.
When i got my HS80s and FS80s, i tried a quick troubleshooting on the carb with no go before replacing and Viola!!!
It has been a few years since i did these and they still run fine.
I could understand for a person who does this for a living to get a part that they know passed QC with Zama on it, but for me and $5 with return \credit gaurantee, I'm game- i keep 2 laying around for future new finds...
 

bertsmobile1

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  • / Stihl FS45, HS80 and HS45-z All Stalling under Acceleration
As a hobbyist myself, i have bought and am ok with carbs from HK. So far 8??for8 and they all run fine.
When i got my HS80s and FS80s, i tried a quick troubleshooting on the carb with no go before replacing and Viola!!!
It has been a few years since i did these and they still run fine.
I could understand for a person who does this for a living to get a part that they know passed QC with Zama on it, but for me and $5 with return \credit gaurantee, I'm game- i keep 2 laying around for future new finds...

Won't get that down here.
Can not count the number of times some one has come in with an "unfixable " piece of gear even after they have fitted a brand new carb.
They pressure test fine then when pulled down have things like butterflys fitted backwards, holes missing from the body, totally wrong pump fitted, no check vale in the body ( that was a hard one to find ).
All of them came off Evilbay and down here once delivered that is it, no returns.
Paypal some times does the right thing but it is fairly hard when you claim the item is defective.
If what you have in your hand looks identical to what was on their photos then you bought what was described as "the picture is part of the description" so it is your fault.

Some of the stuff will be good, some of the stuff will be bad but it is a lottery to find who is selling what.
So the golden rule is no branding on the carb, or packaging , most likely junk.

The profit margins in China are very small so there is no such thing as scrap.
If Poulan rejects a batch of carbs then the batch gets sold as "Poulan OEM carbrettors" , quite true.
Usually they will be bought by a disposal company who will on sell them as "fits Poulan model ABC", also true.
Then they end up at an online retailer, many of which vanish once the stock is all sold.

You have been lucky so far or are buying from a person who knows what they are selling is good.

So if Guy buys parts wholesaled by one of the real distributors mentions who have real buildings and real staff and real insurance thus offer real guarantees then he will get a good part.
If he buys from an fictious on line shop then it is quite frankly pot luck.

I used to run distribution warehouses and we unloaded containers from China, India, Brazil etc etc etc, packed the stuff on pallets then sent them to the final purchaser.
After being burned a few times, we demanded cash up front before we opened the boxes , let alone sorted & stored the goods.
Nothing left the warehouse unless we were paid up front because a month latter a lot of the bank accounts had been closed down and the phone numbers no longer connected.
In most cases I never saw our clients, they rang up, got a quote then rang back with collection details and set up the financials.
If it were up to me I would have nothing to do with them, but I just ran the place and the money we made from selling the excess capacity kept our running cost down.
The invoices / reciepts that went with the goods, were very professional looking many showed a warehouse with the brand name on it and a fleet of branded vehicles, none of which existed anywhere but inside the printer.

I have no idea which on line retailers down here in OZ are good and which are shonks because I only deal with factories or wholesalers thus the reply Guy was given
Now if you went on like, the vendors looked like they were a big well established company whenin reality they were one scumbag with a laptop and all of the photos of stock, & buildings & workers, were faked
 

S Haase

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  • / Stihl FS45, HS80 and HS45-z All Stalling under Acceleration
Hi Guys,

I'm new here and this is my first post. A bit about me..., I like to play and tinker with any engines I can find, usually get them given from familly to fix or buy them not running, service them and get them running good and sell them and start over.

Anyway I have four Sthil machines that I can't get going and I have no idea why?? They all start and Idle fine but when you give them gas they bog down and stall. I have cleaned the flame screen in all of them, Carbs cleaned, worst ones I have put new carb kit in them, Also tried a cheap ebay carb replacement but always the same result, starts and runs fine but bogs down on throttle.

This happens with two FS45, A HS45-z and a HS80..

Using fresh fuel with all of them. Only cleaned the plugs.

What do you guys think? Or what should I be testing/ Looking for?

Thankyou

Thanks
 
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