Chainsaw not running right, any help ?

[Hephaestus29]

My chainsaw is not running right, I dumped the old gas & mixed new but that didn't fix it.

It starts & runs & revs but when you try to give it full throttle for a cut it just bogs down. Thanks for any help

 

[Matt018]

Try to clean the carb and see what happens.

 

[cj7365]

a couple of things to check, air filter, check the fuel lines, my had a small crack and was allowing air, it had the same symtoms as yours, would start but full throttle would stall. If the fuel was in there for over six months, you might need to clean out the carb.

 

[mrobins297aaa]

put some sea foam in there and run it for about 15 minutes, stuff is real good at cleaning the junk out of the carbs

 

[Nak]

The fuel pickup/hose will deteriorate in the tank. Start there.

 

[Hephaestus29]

Thanks for the help, much appreciated.

 

[jabberwoki]

Look at the exhaust there is usually a fine mesh spark arrestor over the exhaust outlet and over time it gets blocked with carbon. Pull it out and throw it away even if it`s not yet blocked.

 

[Skin]

buy a replacement carburetor if you can. If you cant throw it in the trash.

 

[kell0026]

don't use ethenol fuel buy as high of a grade you can with small engines. That stuff will plug up your carb. just pull the carb and clean it out. then check you fuel lines for cracks.

 

[Skin]

don't use ethenol fuel buy as high of a grade you can with small engines. That stuff will plug up your carb. just pull the carb and clean it out. then check you fuel lines for cracks.

grade (octane rating) has no bearing on ethanol content. Unless you happen to be very lucky living near a gas station that has 0 ethanol fuel still the only two options are airport or marinas. Or you can buy the canned stuff for $15 or $20 a gallon.

 

[Snapped-off]

Not sure if it's obvious or not, but it doesn't take much more than a tank of bad gas to scorch a piston in a saw. Looks like you're on the right track though dumping the old gas.

Without any fuel additives, I've always heard gas is only good for a month these days.

Seems previous posters have addressed the most common possible issues.

 

[thebeekeeper1]

Look at the exhaust there is usually a fine mesh spark arrestor over the exhaust outlet and over time it gets blocked with carbon. Pull it out and throw it away even if it`s not yet blocked.

From your description, this ^^^ is your likely problem. The exhaust can't leave--just like the government-mandated 1.6 GPF toilets.

 

[smallie9]

One other thing to consider is the age and overall use of the saw. If they get used anything like mine do, a new piston ring and such may be in order. But of course it is easier and cheaper to try the other options first.

 

[Den69rs96]

First, check your fuel line for cracks and make sure the tank vent is not plugged up. Also make sure the low and high speed screws are set to factory specs or close to it. If the fuel line and fuel filter are good with no cracks, most likely the carb needs a good cleaning. Usually a clogged spark arrestor will not allow the engine to rev, but if its cutting out and bogging down, you have a fuel delivery problem.

 

[HaroRider]

Mine had alot of wood dust in the fuel strainer in the carb.

 

[Davefr]

buy a replacement carburetor if you can. If you cant throw it in the trash.

Randomly throwing parts at it in hopes that it'll solve the problem is poor troubleshooting.

Physical inspection is the best starting point. (fuel delivery, ignition and compression)

 

[Major Ramifications]

grade (octane rating) has no bearing on ethanol content. Unless you happen to be very lucky living near a gas station that has 0 ethanol fuel still the only two options are airport or marinas. Or you can buy the canned stuff for $15 or $20 a gallon.

Wow, are things really that totalitarian up there in the land of the late Ted Kennedy?
There are several gas stations that sell alcohol-free gasoline within a mile or two of my house, that's all I buy. The price is about $3.79 for the regular unleaded right now.
Plus, you will find the south to be much more gun friendly, and as an added bonus, the states are easier to spell. You should come down for a visit.

To the OP, if the gas that was in it smelled funny before you poured it out, then you will need to clean the carburetor thoroughly or replace it. They aren't expensive.
And in the future, use Stabil in all your small engines.

 

[RedFordTruck]

My chainsaw is not running right, I dumped the old gas & mixed new but that didn't fix it.

It starts & runs & revs but when you try to give it full throttle for a cut it just bogs down. Thanks for any help

I had a similar problem with an old B&S edger. It would start and idle fine, but when you revved it it would sputter out and die.

First I siphoned the 6-month old gas out of it and put in fresh gas mixed with seafoam. I drained all the oil and filled it back up with 1/2 new oil, 1/2 seafoam. Then I let it run for 20ish minutes at idle.

(Since you've got a 2-stroke just mix it with the gas)

Then changed the seafoam/oil mix, Cleaned the carb, and figured while I was at it I would replace the air filter and spark plug too.

Runs great now but I dunno which of those things made the biggest difference!

 

[dandan111]

Also,look down in the tank and make sure it's clear. Been down that road..had piece of foam blocking fuel one time.

 

[Scout Driver]

Look at the exhaust there is usually a fine mesh spark arrestor over the exhaust outlet and over time it gets blocked with carbon. Pull it out and throw it away even if it`s not yet blocked.

From your description, this ^^^ is your likely problem. The exhaust can't leave--just like the government-mandated 1.6 GPF toilets.

From my experience, these people are correct ^^^^^. You may not want to toss out the spark-arrestor, but at least clean it and put it back in.

Scott

 

[Skin]

Randomly throwing parts at it in hopes that it'll solve the problem is poor troubleshooting.

Physical inspection is the best starting point. (fuel delivery, ignition and compression)

i'll rebuild a small engine until it cant be anymore but those tiny 2 cycle engines ****. if you fiddled with them on and off under a regular basis you'd know what i mean.

Wow, are things really that totalitarian up there in the land of the late Ted Kennedy?

Most of the country in fact. The deep south seems to be the last hold out.

 

[Katsin]

Donyboy73 on YouTube has many excellent videos on chainsaw maintenance:
http://www.youtube.com/user/donyboy73?feature=chclk

The guy puts a lot of time and effort into his videos.

 

[Imcrazy]

The fuel pickup/hose will deteriorate in the tank. Start there.

Fuel with alcohol in it turns the fuel lines to goo

 

[buildmyown]

Sounds like a clogged carb if it will start idel but bogs and cuts out when going to full throttle. What kind of saw? If its one of the big name ones the carb kits cheap, easy to get and the saws are easy to work on. If its a big box store type saw they are a pain in the azz to work on have to tear the whole saw apart. There aer 3 adjustment screws on the carb idel screw high speed and low speed. Going from memory you could try to adjust the high and low screws. Start the saw and let it idel to the muffler is hot to the touch. Turn the low speed clockwise in till the saw starts to die and then back it out 1 turn now move to the high speed side hit the throttle if the saw does not come off idel clean but stumbles or dies back the high screw out an 1/8 of a turn and try it again. Keep going till the saw comes off idel clean dont go more then 3 turns out. Again alot depends on the type of saw but that is basic tunning .

 

[DHS]

I had a coworkers Husky that would start and rev once and then die. It was the fuel line deteriorated and pieces would clog the screen in the carb. New fuel line and a quick carb cleaning and it was running great once again.

I hate small 2 strokes... but rarely ever have a problem with mine. I buy non ethanol gas and use Stabil.

 

[bob15]

buy a replacement carburetor if you can. If you cant throw it in the trash.

Why not just spend $10 and get a rebuild kit? I guess I should throw my McCulloch SP-125 away because I need a rebuild kit??? Yea right......

 

[DHS]

Also what are you working on, you did not say or at least I did not see, haha.

 

[joshmodelskidoo]

i would bet your carb is dirty. get a can of carb cleaner and pull out the pilot and main jet and spray them out. spray down your needle and seat cause u might not be getting enough gas. check youtube for carb cleaning vids. chainge your spark plug.

 

[TreePointer]

You don't have to throw away your spark arrestor. If dirty, just take one of those torch style cigarette lighters and burn off the carbon/deposits. It will get red hot so hold it with some pliers, but it will not harm the screen.

 

[TreePointer]

What saw model? (Don't be embarrassed. They all have a purpose and place in the market.)

What octane fuel are you using?
What 2-cycle oil are you using?
What mix ratio are you using? 50:1? Other?

 

[buco]

Don't mean to hijack the thread...

I was falling a tree yesterday with my dad's saw and after running for about 5 minutes it quit. Then after about a half hour it fired up again' then stalled again after a minute.

When I give her a yank I felt the pull is tighter than it should be, still pulls fine but it's stiffer than normal. When I opened the gas tank i heard it hissing for air.

I've got new gas and new oil, chain bar is getting oil. The saw didn't have old gas in it and was empty.

It's a stihl 440 magnum btw.

 

[stoveboltgunnut]

You have a hole in a fuel line

 

[sometoyotaguy]

Don't mean to hijack the thread...

I was falling a tree yesterday with my dad's saw and after running for about 5 minutes it quit. Then after about a half hour it fired up again' then stalled again after a minute.

When I give her a yank I felt the pull is tighter than it should be, still pulls fine but it's stiffer than normal. When I opened the gas tank i heard it hissing for air.

I've got new gas and new oil, chain bar is getting oil. The saw didn't have old gas in it and was empty.

It's a stihl 440 magnum btw.

Clean your tank vent, or replace it.

 

[sometoyotaguy]

It sounds like your exhaust screen is plugged. I got a free weedeater that way. It would run, but didn't have any power.

If that doesn't fix it, check your fuel filter and lines.

Then, get a rebuild kit for your carb, they are $8 or so, and rebuild it. Make sure you clear out the passages and screen with carb cleaner.

Saws aren't that bad unless you have to replace bearings or seals.