Chainsaw was running a bit rough today...

[EatenByLimestone]

After a stop to refuel and refill bar oil I pulled out my ear plugs.

When I restarted the saw, it seemed to be running a little rough. This may have been my imagination though... my foam earplugs had not expanded to block out the sound yet. I usually have them in for a while before the chainsaw is started. My father was using the saw yesterday and didn't mention any strange sounds.

How much of a change in altitude do you have to experience before the carb is thrown out of adjustment? I live in an area ~200 feet above sea level. The place I was cutting was ~1000ft. This doesn't seem like enough to cause a difference so I figured that it's probably my imagination.

Would this difference in altitude explain the possible rough running? The chainsaw ran fine otherwise... I had to do 2 quick touchups on the chain due to the amount of wood I processed, but the saw did fine.

Matt

 

[Mike]

EBL, I'm no chain saw expert, but the (partial) pressure change between 200 and 1000 should not be significant. In my experience, it does not have any significant effect on equipt like breathing apparatus, sensors, etc. Move up a few thou, and there will be a difference.

Mountain men?

 

[Roospike]

Do you use fuel stablizer ?
Do you use fresh gas?
What octane?
Gas with corn mix?
Do you dump out the old fuel in the saw & put in fresh before using after its been stored ?
When if ever has the carb been adjusted sense new ?
How old is the chainsaw?
What brand?
What model?
What mix ratio (oil/gas) do you use?
What fuel ratio gas/oil does your dad use?
Did/does he (your dad) always use fresh gas?
Whats the spark plug look like?
How often do you change the spark plug?
Is the spark plug gaped correct?
Is your exhaust screen clean? ~
How often do you clean the screen if ever?
Air filter clean?
How often do you clean the air filter?
Does the carb have/get dust dirt in it?
Does it now?

 

[DriftWood]

My guess; it's a dirty air filter. could be fuel you added is bad or old. The only time I really need to reset the jets in when the seasons change hot dry summer to cold wet fall.

 

[EatenByLimestone]

Do you use fuel stablizer ? 1 oz. Sta-bil added to 2 gal of gas.
Do you use fresh gas? Purchased 2 days ago.
What octane? 87 octane- Is this too low?
Gas with corn mix? No idea. Different gas than my father used though. I left the old can with him and filled a new one.
Do you dump out the old fuel in the saw & put in fresh before using after its been stored ? It's rarely stored. Or was not all summer long
When if ever has the carb been adjusted sense new ? It hasn't been since I've started using it. Not sure if my father did. Probably not.
How old is the chainsaw? 2-3 years.
What brand? Craftsman.
What model? 42 CC, 18" bar.
What mix ratio (oil/gas) do you use? 40:1
What fuel ratio gas/oil does your dad use? Same.
Did/does he (your dad) always use fresh gas? Yes. We have used a few cans of it this year. Probably burnt 4-5 gallons since sp.
Whats the spark plug look like? Have not pulled it. Changed it this fall.
How often do you change the spark plug?
Is the spark plug gaped correct? We gapped it this fall, if I remember 35 thousandths...
Is your exhaust screen clean? ~ I didn't know one existed. I'll check it.
How often do you clean the screen if ever?
Air filter clean? Yes.
How often do you clean the air filter? Cleaned this fall when I went over it and changed the plug.
Does the carb have/get dust dirt in it? Hopefully not, but it's not the cleanest working environment...
Does it now? I'll check and get back to you.

Checked the air filter. It had some sawdust on it, but was in no way restricted. I cleaned it off when I peaked behind the sponge. It was clean back there. It doesn't look like anything got behind the oiled sponge to the carb. I suppose that some sawdust could have made it's way into the fuel at a fill up though. Is there a fuel filter of sorts on this thing?



Edit to correct and add some info.

 

[Roospike]

This is where i would start @

Do you use fuel stablizer ? 1 oz. Sta-bil added to 2 gal of gas.
Do you use fresh gas? Purchased 2 days ago.
@What octane? 87 octane- Is this too low? use high octane. It burns cleaner and cooler.
@Gas with corn mix? No idea. Different gas than my father used though. I left the old can with him and filled a new one. Its best not to use corn mix. corn will draw moisture into the fuel and it also separates gas and oils
Do you dump out the old fuel in the saw & put in fresh before using after its been stored ? It's rarely stored. Or was not all summer long
@When if ever has the carb been adjusted sense new ? It hasn't been since I've started using it. Not sure if my father did. Probably not. Carb should be adjusted after 10 tanks of gas from new and checked every year.
@How old is the chainsaw? 2-3 years. might be getting past its time.
What brand? Craftsman.
What model? 42 CC, 18" bar.
What mix ratio (oil/gas) do you use? 40:1
What fuel ratio gas/oil does your dad use? Same.
Did/does he (your dad) always use fresh gas? Yes. We have used a few cans of it this year. Probably burnt 4-5 gallons since sp.
Whats the spark plug look like? Have not pulled it. Changed it this fall.
How often do you change the spark plug?
Is the spark plug gaped correct? We gapped it this fall, if I remember 35 thousandths...
Is your exhaust screen clean? ~ I didn't know one existed. I'll check it.
@How often do you clean the screen if ever? Check exhause screen for build up, clean with a small wire brush. It will be in the exhaust hole of your muffler or inside the muffler.
Air filter clean? Yes.
@How often do you clean the air filter? Cleaned this fall when I went over it and changed the plug. Its good practic to clean the air filter about every other tank of gas used.
Does the carb have/get dust dirt in it? Hopefully not, but it's not the cleanest working environment...
Does it now? I'll check and get back to you.

Checked the air filter. It had some sawdust on it, but was in no way restricted. I cleaned it off when I peaked behind the sponge. It was clean back there. It doesn't look like anything got behind the oiled sponge to the carb. I suppose that some sawdust could have made it's way into the fuel at a fill up though.
@ Is there a fuel filter of sorts on this thing?Yes there is a fuel filter in the tank , take a stiff wire or coat hanger and make a small hook on the end .... put it in the tank and fish out the fuel line/filter. Its best to replace every year.



Edit to correct and add some info.

 

[ourhouse]

This is where i would start @

Do you use fuel stablizer ? 1 oz. Sta-bil added to 2 gal of gas.
Do you use fresh gas? Purchased 2 days ago.
@What octane? 87 octane- Is this too low? use high octane. It burns cleaner and cooler.
@Gas with corn mix? No idea. Different gas than my father used though. I left the old can with him and filled a new one. Its best not to use corn mix. corn will draw moisture into the fuel and it also separates gas and oils
Do you dump out the old fuel in the saw & put in fresh before using after its been stored ? It's rarely stored. Or was not all summer long
@When if ever has the carb been adjusted sense new ? It hasn't been since I've started using it. Not sure if my father did. Probably not. Carb should be adjusted after 10 tanks of gas from new and checked every year.
@How old is the chainsaw? 2-3 years. might be getting past its time.
What brand? Craftsman.
What model? 42 CC, 18" bar.
What mix ratio (oil/gas) do you use? 40:1
What fuel ratio gas/oil does your dad use? Same.


Did/does he (your dad) always use fresh gas? Yes. We have used a few cans of it this year. Probably burnt 4-5 gallons since sp.
Whats the spark plug look like? Have not pulled it. Changed it this fall.
How often do you change the spark plug?
Is the spark plug gaped correct? We gapped it this fall, if I remember 35 thousandths...
Is your exhaust screen clean? ~ I didn't know one existed. I'll check it.
@How often do you clean the screen if ever? Check exhause screen for build up, clean with a small wire brush. It will be in the exhaust hole of your muffler or inside the muffler.
Air filter clean? Yes.
@How often do you clean the air filter? Cleaned this fall when I went over it and changed the plug. Its good practic to clean the air filter about every other tank of gas used.
Does the carb have/get dust dirt in it? Hopefully not, but it's not the cleanest working environment...
Does it now? I'll check and get back to you.

Checked the air filter. It had some sawdust on it, but was in no way restricted. I cleaned it off when I peaked behind the sponge. It was clean back there. It doesn't look like anything got behind the oiled sponge to the carb. I suppose that some sawdust could have made it's way into the fuel at a fill up though.
@ Is there a fuel filter of sorts on this thing?Yes there is a fuel filter in the tank , take a stiff wire or coat hanger and make a small hook on the end .... put it in the tank and fish out the fuel line/filter. Its best to replace every year.



Edit to correct and add some info.

That about covers it.

 

[quads]

Sometimes a change in the weather/temperature/humidity will make them run a little different than they did the day before. With the older saws you could just tweak the carb adjustments a little, but not so with a lot of the newer ones.

 

[wahoowad]

thanks, I was wondering where that fuel filter was located!

 

[BurningIsLove]

Im guessing that comment about "2-3 years being past its time" was a joke?

The first chainsaw I used was older than I was at time (15 years), and 10 years later it was still reliable & powerful (my father uses it to this day 20 years later) If you cant get at least 10 years out of a saw (or lawnmower, or tractor, or any other yard tool), you are throwing money into the wind. A few bucks and a few hours of preventative maintenance each year will be enough to make your tools last decades... My mower, tractor, chainsaw, chipper, etc. are all 10+ years old and still chuggin as good as ever. The obvious exception is if you are chainsawing for a living, in which case your saw probably will be worn quicker due to excessive use.

That being said....the keys to a well running chainsaw I've found (outside of regular, preventative mainenance) are:

fresh gas: proper storage will make gas last longer especially if you mix fresh 2-cycle as needed instead of storing it mixed

clean/replace air filter regularly: takes all of 60 seconds for either. Use older gas (non-mixed) to clean an existing filter to really clean it nicely

check the plug/gap. the gap doesnt need to be changed often, but just clean off sediment w/ old, non-mixed gas just like a filter.

take the bar off and clean the sawdust/oil chunder off regularly. It's quick & easy, I do it about 3-4 sharpenings of the chain.

if auto-bar oil dispensing, clean out the dispenser tube as this gets clogged w/ sawdust/matter now matter how careful you are.

 

[Roospike]

Im guessing that comment about "2-3 years being past its time" was a joke?

The first chainsaw I used was older than I was at time (15 years), and 10 years later it was still reliable & powerful (my father uses it to this day 20 years later) If you cant get at least 10 years out of a saw (or lawnmower, or tractor, or any other yard tool), you are throwing money into the wind. A few bucks and a few hours of preventative maintenance each year will be enough to make your tools last decades... My mower, tractor, chainsaw, chipper, etc. are all 10+ years old and still chuggin as good as ever. The obvious exception is if you are chainsawing for a living, in which case your saw probably will be worn quicker due to excessive use.

That being said....the keys to a well running chainsaw I've found (outside of regular, preventative mainenance) are:

fresh gas: proper storage will make gas last longer especially if you mix fresh 2-cycle as needed instead of storing it mixed

clean/replace air filter regularly: takes all of 60 seconds for either. Use older gas (non-mixed) to clean an existing filter to really clean it nicely

check the plug/gap. the gap doesnt need to be changed often, but just clean off sediment w/ old, non-mixed gas just like a filter.

take the bar off and clean the sawdust/oil chunder off regularly. It's quick & easy, I do it about 3-4 sharpenings of the chain.

if auto-bar oil dispensing, clean out the dispenser tube as this gets clogged w/ sawdust/matter now matter how careful you are.

Nope , no joke but you understand it tho. "excessive use" is a hard one to explain and so many factors go into it.
A big issue is getting an undersized tool and doing more for what it was made to do.

A Ford ranger might be able to pull a car trailer w/car but its not going to last as it should pulling cars all the time.

 

[BurningIsLove]

Of course.....the 'little engine that could' doesnt apply to long term felling of trees. If you fell/buck your own trees as your primary fuel source, you dont want to buy the Better Crocker Easy-Bake Chainsaw. Make the investment up front in a saw that will is maintable as long as you can find parts for it.

If none of what everone has posted works out, you might also want to test the compression of the piston to make sure you havent cracked a ring. When you have the cover off and the carb exposed, do the ole thumb trick over the exhaust port (if accessible) and see if there is a drastic difference. Sometimes that isnt a good measure for engines that small. Make sure to also be very careful w/ your thumb that close to a spinning blade.

 

[Roospike]

Normally some of the first things checked per a saw shop would be ...........

compression
gas fuel mix
air filter
fuel line leak/crack ( i forgot to add to the above post of questions )
Spark.. coil/plug
case & carb air leaks
carb settings & rmp test
exhaust / muffler screen blockage

 

[EatenByLimestone]

I pulled the muffler off and it was clean. Maybe it was my imagination that the saw was running rough... Maybe the difference in sound between when the earplugs were sealed vs. unsealed?

I'll have it going this weekend. I'll check it again then.

There was a mention of humidity in an earlier post. Last weekend the weather was pretty miserable. A light on and off rain all day long.

Matt

 

[MikeS]

check hardware mounts (engine mounting screws).

the broken or cracked fuel line is an important check. air leaking in there will make your saw lean out as soon as the fuel level gets below the crack/break (lean, but not "rough")

dirty air filter could make it a bit rich, which could be construed as "rough."

dirty air filter plus +1000 feet elevation change could make seem rough (due to richness). Check for smoke. extra smoke is usually a sign of rich.

I agree that only 1000 feet should not change anything. but 1000 feet plus dirty air filter could enrichen things.

ms

 

[Rich M]

I'm guessing earplugs. I had an old Craftsman (it was made by Poulan and branded by Sears as Craftsman) and it really had a rough, rumbling tone at idle, especially when heard without hearing protection.

 

[Jay H]

Whooaaa... should I not be using regular gasoline with 10% ethynol then? I just read the corn-gas thing here.... wondering if I should switch gas brands, I got my latest gas/blend from Hess with uses 10% ethynol.... I've been using that in my gas splitter actually but I need to mix another gallon for my husky.

Also, what should I be adjusting on my carburater after the 10 hours, my 359 should be roughly close to 10 hours soon.... No tachymeter, but would I be able to do this by ear, trial and error?

Jay

 

[tradergordo]

Whooaaa... should I not be using regular gasoline with 10% ethynol then? I just read the corn-gas thing here.... wondering if I should switch gas brands, I got my latest gas/blend from Hess with uses 10% ethynol.... I've been using that in my gas splitter actually but I need to mix another gallon for my husky.

Also, what should I be adjusting on my carburater after the 10 hours, my 359 should be roughly close to 10 hours soon.... No tachymeter, but would I be able to do this by ear, trial and error?

Jay

I'm not even sure where you can find gas that doesn't have ethanol in it anymore - wasn't it federally mandated that they add it? Every station around me has signs that say "contains ethanol". I agree though, because it attracts water, its not ideal to store gas with ethanol for your tools - in the very least, you should make sure your container is airtight.

As for adjusting the carb, see:
http://web.archive.org/web/20051228040631/www.madsens1.com/sawtune.htm