Help, my chainsaw is running roughly

New Avon Arms
M

muddy42

Well-Known Member
This is very much off-topic, but I gather there are some knowledgeable chainsaw users on here.

I have a 5 year old Husqvana 135, its small at only 38 cc or so. The saw starts OK and idles well, but at high revs the sound is a bit uneven, when I apply load (cutting wood) it gets worse, the saw bogs down and looses power.

This feels like a lack of fuel issue to me. So far I have rinsed out the fuel tank with neat petrol, replaced the fuel filter, cleaned the air filter and spark plug. The petrol is premium petrol bought under a month ago from the pump and mixed accurately to 50:1 by me only a week ago. The fuel works fine in my other saw, a larger and older Stihl. The chain is sharp and oiling well.

Any ideas? I was thinking of trying some Aspen. I don't really feel confident enough to go replacing carburetors or fuel lines.
 
muddy42 said:
This is very much off-topic, but I gather there are some knowledgeable chainsaw users on here.

I have a 5 year old Husqvana 135, its small at only 38 cc or so. The saw starts OK and idles well, but at high revs the sound is a bit uneven, when I apply load (cutting wood) it gets worse, the saw bogs down and looses power.

This feels like a lack of fuel issue to me. So far I have rinsed out the fuel tank with neat petrol, replaced the fuel filter, cleaned the air filter and spark plug. The petrol is premium petrol bought under a month ago from the pump and mixed accurately to 50:1 by me only a week ago. The fuel works fine in my other saw, a larger and older Stihl. The chain is sharp and oiling well.

Any ideas? I was thinking of trying some Aspen. I don't really feel confident enough to go replacing carburetors or fuel lines.
Click to expand...
Sounds like you need a new carburettor.
 
Has the saw been in regular use?

Was it left with fuel in it for a few months?

Is it old enough to have screw adjustable jets?

Do you have access to an Ultrasonic cleaner?

I generally replace the plug at the first sign of problem.

But the little carburettors on my old Stihl saw and the Husqvarna hedge trimmer were easy enough to service and rebuild with new diagphrams etc.. But if you don't feel up to it yourself, have you ever taken the machine in to be serviced?

Alan
 
Frank Homes said:
Sounds like you need a new carburettor.
Click to expand...
Ha, this is what I feared.
long_range_rob said:
Could it be an E10 fuel issue. I always empty the tank and run the saw till it’s dry if fuel when I’m not using it for a few days as fuel seems to go stale very quickly these days, particularly in carbs.
Click to expand...

Alantoo said:
Has the saw been in regular use?

Was it left with fuel in it for a few months?

Is it old enough to have screw adjustable jets?

Do you have access to an Ultrasonic cleaner?

I generally replace the plug at the first sign of problem.

But the little carburettors on my old Stihl saw and the Husqvarna hedge trimmer were easy enough to service and rebuild with new diagphrams etc.. But if you don't feel up to it yourself, have you ever taken the machine in to be serviced?

Alan
Click to expand...
Yes the saw has been in regular use. It was used only on Aspen until December, then regularly used again.

It has adjustable jets.

I dont have an ultrasonic cleaner.
 
Might just need the high adjustment screw adjusting. To be honest if it's bogging down it most likely is to rich on the H screw. It'll be a tiny amount of adjustment.
A small screw driver on the screw and hold the trigger so it's running flat out and adjust so it runs sweet.
Sometimes if the low or L screw is to rich it can influence a wide open throttle settings ( the H screw) but usually if that is wrong it has issues ticking over etc etc. You say it's fine there so I would go the H screw with the engine running flat out.
The only other thing is that some huskies have a cold weather flap that directs some warm air over the carb to prevent carb freezing, a similar symptom to your description. Check the manual for that.
 
Smellydog said:
Might just need the high adjustment screw adjusting. To be honest if it's bogging down it most likely is to rich on the H screw. It'll be a tiny amount of adjustment.
A small screw driver on the screw and hold the trigger so it's running flat out and adjust so it runs sweet.
Sometimes if the low or L screw is to rich it can influence a wide open throttle settings ( the H screw) but usually if that is wrong it has issues ticking over etc etc. You say it's fine there so I would go the H screw with the engine running flat out.
The only other thing is that some huskies have a cold weather flap that directs some warm air over the carb to prevent carb freezing, a similar symptom to your description. Check the manual for that.
Click to expand...

David Barker said:
Re set the High and low settings a wee bit fiddly but might sort your problem . It did on mine

Click to expand...

I've adjusted those screws before on a different saw. These were checked by a shop a while ago. I'm not convinced that is the issue. This is more than just lack of RPM on the high screw, its bogging down/loss of power.
 
Alantoo said:
Has the saw been in regular use?

Was it left with fuel in it for a few months?

Is it old enough to have screw adjustable jets?

Do you have access to an Ultrasonic cleaner?

I generally replace the plug at the first sign of problem.

But the little carburettors on my old Stihl saw and the Husqvarna hedge trimmer were easy enough to service and rebuild with new diagphrams etc.. But if you don't feel up to it yourself, have you ever taken the machine in to be serviced?

Alan
Click to expand...
If you want to do it yourself have a look on U Tube first.
 
muddy42 said:
I've adjusted those screws before on a different saw. These were checked by a shop a while ago. I'm not convinced that is the issue. This is more than just lack of RPM on the high screw, its bogging down/loss of power.
Click to expand...
I recently fixed a neighbours 240e husqy that was bogging down, needed the plug cleaned, gap set and the High mixture screw tweaked while holding at full chat.

Regards,
Gixer
 
With almost any 2 stroke problem, new plug and clean/new air filter.

Doesn't always solve it, but cheap, easy and does no harm and surprising how many problems it does solve.
And then newly mixed petrol/2 stroke.

If ur not confident about adjusting ur H and L screws, u should be able to find the factory settings either in manual or internet, i think husky used to be 1 and 1 but i know some of my stihls are all sorts.
I never muck about with the H too much as u can damage the saw

1 of the lads at work was saying the oppisate to me that the premium fuel is not good for saws and burns the injectors out or something, so no idea i might start going back to normal fuel instead,
I have heard it said not a good idea to mix using aspen and 2 stroke as it reacts and perishes pipes, fine if u stick to 1 or the other.

I take it still plenty of compression? Nothing could have damaged the ring or anything?
 
countrryboy said:
With almost any 2 stroke problem, new plug and clean/new air filter.

Doesn't always solve it, but cheap, easy and does no harm and surprising how many problems it does solve.
And then newly mixed petrol/2 stroke.

If ur not confident about adjusting ur H and L screws, u should be able to find the factory settings either in manual or internet, i think husky used to be 1 and 1 but i know some of my stihls are all sorts.
I never muck about with the H too much as u can damage the saw

1 of the lads at work was saying the oppisate to me that the premium fuel is not good for saws and burns the injectors out or something, so no idea i might start going back to normal fuel instead,
I have heard it said not a good idea to mix using aspen and 2 stroke as it reacts and perishes pipes, fine if u stick to 1 or the other.

I take it still plenty of compression? Nothing could have damaged the ring or anything?
Click to expand...
Yes plenty on compression.
The spark plug was new in December, but I am not adverse to trying another new one
 
My little 181 kept doing something similar, juddery on full throttle that’s when I could get it to full throttle as it bogged down. Took the spark plug out it was fine. Did it again a few weeks later and I realised the spark plug boot was being knocked too far over the plug. It stopped doing it as soon as I remove and replace the boot. If you replaced the spark plug so recently and your having issues immediate might be worth a look
 
muddy42 said:
I've adjusted those screws before on a different saw. These were checked by a shop a while ago. I'm not convinced that is the issue. This is more than just lack of RPM on the high screw, its bogging down/loss of power.
Click to expand...
It will bog down if to rich. Rev very high if to weak but then there is the risk of damage. One takes it until it starts to scream and the riches to the point one can just hear it hunting. Lean it off again and you are done.
Taking it to a shop means nothing!
 
If you have tried all the above and don't want to buy a new carb or have access to a ultrasonic bath.
Boil it for half hour in water and vinegar or soapy water. Not that i know much about engines....
 
You must log in or register to reply here.

Similar threads

Short petrol chainsaw for brush work, advice required.
Replies
18
Views
650
Will the chippy
W
Dead Freelander!
2 3
Replies
54
Views
2K
greenhillstairs
greenhillstairs
Chainsaw recommendation please
2 3
Replies
56
Views
3K
countrryboy
C
Chainsaw recommendations
2
Replies
25
Views
1K
olliehopes
O
Chainsaw Safety Lesson...
2 3
Replies
50
Views
3K
User00056
U
Savage 110 Carbon Tactical - Unmatched Precision - Viking Arms
Back
Top