Chainsaw bogs down no power

[Dozer310]

Have a cheaper Poulan chainsaw that runs fine for the first five minutes and then will idle okay but will have no power I can just press the throttle and it almost dies out let go and it will come back to idle. made adjustments need advice

 

[Hogwildz]

Sounds like carb is gummed up, and not getting steady fuel flow. Prolly a clog somewhere. Pull the carb and clean it up, including all orifices.

 

[Easy Livin’ 3000]

Have a cheaper Poulan chainsaw that runs fine for the first five minutes and then will idle okay but will have no power I can just press the throttle and it almost dies out let go and it will come back to idle. made adjustments need advice

May also be fuel line problems. When you are done cleaning the "orifices" (thanks sportsbikerider), replace the lines. Oh, and have you replaced the air filter?

 

[Sean McGillicuddy]

Fuel filter should also be changed.

 

[lsucet]

For how long do you have it. If it is new, sometimes it needs to be tuned, not always they are tuned right out of the box. I have the 50cc pro with 20" bar and I have to tuned the carburetor when I bought it. It works like a champ after I replace the chain with a full chisel one.

 

[lsucet]

I am based on your statement that it runs fine for the first five minutes and then starts to give you problem but it idles fine. If too reach, can give you that condition once it starts to warm up.

 

[Easy Livin’ 3000]

Small engine carb adjustment is not for the faint of heart. I'm as good at it as I am at freehand chain sharpening- not at all. Even figuring out the tool to use is difficult!

 

[burnham]

When my Makita was doing that it turned out to be a plugged vent in the gas tank.

 

[jetsam]

Small engine carb adjustment is not for the faint of heart. I'm as good at it as I am at freehand chain sharpening- not at all. Even figuring out the tool to use is difficult!

It's really not bad at all once you do it a couple of times.

Usually it's a matter of turning 3 screws to the right spots.

Clean the air filter and exhaust, fill up with fresh gas, remove adjustment limiters if installed, warm up the saw, adjust screws. I do them in this order: idle/low/idle/high/low/idle.

For idle adjustments, you are looking for the spot where the engine runs smoothly but the chain doesn't move (or the idle RPM out of the saw's manual, if you use a tachometer). Both of my saws idle happily far below the zone where the clutch engages, so it's not a search for the perfect spot.

For low adjustments, you are adjusting it lean until it runs rough (note position) and then rich until it runs rough (note position), then find the sweet spot in the middle of those two settings.

For high adjustments, you are running the saw at wide open throttle. Adjust lean until it runs rough, adjust rich until it runs rough, find the sweet spot in the middle, then go a teensy bit richer. Can also use a tachometer to hit the specified RPM.

Only takes a couple minutes with a screwdriver. Getting the saws cleaned up and gassed up and ready to start takes longer than the adjustment. The only tools I need for my saws are a small flat screwdriver and a regular scrench (and I only need the scrench because I obsessively adjust the chain before I do the carb).

 

[Easy Livin’ 3000]

It's really not bad at all once you do it a couple of times.

Usually it's a matter of turning 3 screws to the right spots.

Clean the air filter and exhaust, fill up with fresh gas, remove adjustment limiters if installed, warm up the saw, adjust screws. I do them in this order: idle/low/idle/high/low/idle.

For idle adjustments, you are looking for the spot where the engine runs smoothly but the chain doesn't move (or the idle RPM out of the saw's manual, if you use a tachometer). Both of my saws idle happily far below the zone where the clutch engages, so it's not a search for the perfect spot.

For low adjustments, you are adjusting it lean until it runs rough (note position) and then rich until it runs rough (note position), then find the sweet spot in the middle of those two settings.

For high adjustments, you are running the saw at wide open throttle. Adjust lean until it runs rough, adjust rich until it runs rough, find the sweet spot in the middle, then go a teensy bit richer. Can also use a tachometer to hit the specified RPM.

Only takes a couple minutes with a screwdriver. Getting the saws cleaned up and gassed up and ready to start takes longer than the adjustment. The only tools I need for my saws are a small flat screwdriver and a regular scrench (and I only need the scrench because I obsessively adjust the chain before I do the carb).

You have my admiration! Even your instructions, which I believe you made as clear as could be, made my head spin. And I'm a decent mechanic generally.

It's like sharpening the chains, simple in theory and some do it like it's instinct, just get the angles right and the bumper down right. In practice, to me, it's like artistry.

I had a buddy when I was in high school who could shoot an arrow up into the air, about 45° from level, then hit the arrow where it was stuck in the ground with his 22 with iron sites, from the standing position, with almost 100% success. When I couldn't ever hit the arrow, he took my gun to see if it needed sighting in. And guess what? He hit the arrow on the first shot.

Wish I had the knack, or at least had a friend that had the knack, both for the carbs and chains.

 

[lsucet]

You have my admiration! Even your instructions, which I believe you made as clear as could be, made my head spin. And I'm a decent mechanic generally.

It's like sharpening the chains, simple in theory and some do it like it's instinct, just get the angles right and the bumper down right. In practice, to me, it's like artistry.

I had a buddy when I was in high school who could shoot an arrow up into the air, about 45° from level, then hit the arrow where it was stuck in the ground with his 22 with iron sites, from the standing position, with almost 100% success. When I couldn't ever hit the arrow, he took my gun to see if it needed sighting in. And guess what? He hit the arrow on the first shot.

Wish I had the knack, or at least had a friend that had the knack, both for the carbs and chains.

It will get to you with some practice. Who knows for how long your friend was doing it. I bought at the beginning, chain sharpening guide, plus this and that.lol

In no time I was doing everything without of those things.lol Funny ah.
Consistency in something is what gives you that. But, still, there is tools to help you with the task, file guide,depth gauges, etc.

 

[jetsam]

You have my admiration! Even your instructions, which I believe you made as clear as could be, made my head spin. And I'm a decent mechanic generally.

It's like sharpening the chains, simple in theory and some do it like it's instinct, just get the angles right and the bumper down right. In practice, to me, it's like artistry.

I had a buddy when I was in high school who could shoot an arrow up into the air, about 45° from level, then hit the arrow where it was stuck in the ground with his 22 with iron sites, from the standing position, with almost 100% success. When I couldn't ever hit the arrow, he took my gun to see if it needed sighting in. And guess what? He hit the arrow on the first shot.

Wish I had the knack, or at least had a friend that had the knack, both for the carbs and chains.

Well, there's a lot less knack AND a lot less practice involved in chain sharpening and carb adjustment than there is in hitting a 1/4" target with a .22.

I was a little intimidated the first time, too. Jump in and do it, and you will be able to do it fine. Carb adjustment is simpler than chain sharpening too (if the carb is working properly).

 

[DaveInPhilly]

It's really not bad at all once you do it a couple of times.

Usually it's a matter of turning 3 screws to the right spots.

Clean the air filter and exhaust, fill up with fresh gas, remove adjustment limiters if installed, warm up the saw, adjust screws. I do them in this order: idle/low/idle/high/low/idle.

For idle adjustments, you are looking for the spot where the engine runs smoothly but the chain doesn't move (or the idle RPM out of the saw's manual, if you use a tachometer). Both of my saws idle happily far below the zone where the clutch engages, so it's not a search for the perfect spot.

For low adjustments, you are adjusting it lean until it runs rough (note position) and then rich until it runs rough (note position), then find the sweet spot in the middle of those two settings.

For high adjustments, you are running the saw at wide open throttle. Adjust lean until it runs rough, adjust rich until it runs rough, find the sweet spot in the middle, then go a teensy bit richer. Can also use a tachometer to hit the specified RPM.

Only takes a couple minutes with a screwdriver. Getting the saws cleaned up and gassed up and ready to start takes longer than the adjustment. The only tools I need for my saws are a small flat screwdriver and a regular scrench (and I only need the scrench because I obsessively adjust the chain before I do the carb).

Hey man - quick question that's going to show my ignorance here:

As background: I'm trying to get a hand-me-down Poulan Pro saw running. Without replacing anything yet, I was able to get it to the point where it will idle and run wide open, but as soon as I point the bar down, the saw dies. I'm hoping its just a fuel line issue. I got new lines but haven't put them in yet.

In any event, I don't think my saw has a dedicated idle screw. I only see two adjustment screws L and H. Your point about the saw running smoothly while the chain doesn't move hit home because at idle the saw bounces all over the place and the chain creeps ever so slightly. I wasn't sure if this was an adjustment issue or just a function this being a low end saw.

Any ideas?

 

[jetsam]

Hey man - quick question that's going to show my ignorance here:

As background: I'm trying to get a hand-me-down Poulan Pro saw running. Without replacing anything yet, I was able to get it to the point where it will idle and run wide open, but as soon as I point the bar down, the saw dies. I'm hoping its just a fuel line issue. I got new lines but haven't put them in yet.

In any event, I don't think my saw has a dedicated idle screw. I only see two adjustment screws L and H. Your point about the saw running smoothly while the chain doesn't move hit home because at idle the saw bounces all over the place and the chain creeps ever so slightly. I wasn't sure if this was an adjustment issue or just a function this being a low end saw.

Any ideas?

There is most likely an idle adjustment that you're missing. I am no expert, but every carb I've ever worked on, cars, motorcycles, chainsaws, lawnmowers, etc- every one of 'em has had an idle adjustment. Maybe it doesn't look like the others, but it connects to the carb, so it shouldn't be a long search.

If the engine dies when you tip the saw forward a little, I would say don't even mess with trying to adjustment until you fix that. Maybe the fuel line is getting kinked or squashed (inside or outside the gas tank... Remember that there's a filter on a piece of line inside the tank) or a chunk of something is in the carb, or a diaphragm is damaged. Could also be an air leak.

 

[dougand3]

I'm trying to get a hand-me-down Poulan Pro saw running.

The model # would help. If saw is 1990s and newer, the idle screw is a phillips with taper on the end. It sits apart from H-L screws, either above or below. See the lone screw above the H-L screws in this pic.

 

[DaveInPhilly]

The model # would help. If saw is 1990s and newer, the idle screw is a phillips with taper on the end. It sits apart from H-L screws, either above or below. See the lone screw above the H-L screws in this pic.

Its a Poulan Pro 220 (38cc, 16in bar.) No clue how old it is. My dad picked it up second or third hand, used it for a while then gave it to me when it stopped working.

Son of a gun...its right there. It was so caked with gunk I didn't even notice it.

Many thanks my friend.

 

[Sean McGillicuddy]

is your friend!

 

[jatoxico]

Can you confirm the weighted filter in the tank is submerged in the gas when you point the nose down? Can you cut or does it bog down under load?

 

[DaveInPhilly]

Can you confirm the weighted filter in the tank is submerged in the gas when you point the nose down? Can you cut or does it bog down under load?

Sure, the filter stays submerged...trouble is the rest of the line doesn't. Darn thing fell apart. I have new lines and a new filter for it, just need to take the time to put them in.

It never really bogged down, cuts fine until I point it nose down, then it dies. Given the condition of the line, I'm pretty sure that's the culprit, but I won't rule out anything more serious until I get the new lines in and the saw up and running.

 

[jatoxico]

Sure, the filter stays submerged...trouble is the rest of the line doesn't. Darn thing fell apart. I have new lines and a new filter for it, just need to take the time to put them in.

It never really bogged down, cuts fine until I point it nose down, then it dies. Given the condition of the line, I'm pretty sure that's the culprit, but I won't rule out anything more serious until I get the new lines in and the saw up and running.

You're most likely right. May be nicked and/or otherwise beat up where it passes into the tank and that lets it suck air.

 

[Tar12]

Ethanol is not your friend...plays hell on hoses..

 

[DaveInPhilly]

New lines in, saw runs like a champ. Still got to get the carb dialed in, I can't seem to stop the chain from creeping, but at least it doesn't dance all over the driveway. It also spits out oil (literally sprays it out 5-6 feet) so that's the next problem to tackle.

 

[jatoxico]

New lines in, saw runs like a champ. Still got to get the carb dialed in,

Nice. There are several good videos on carb adjustment on youtube, one of the ones I liked was using an older Poulan. Basically start with both screws out about 1 1/2 to 2 turns out as a starting point. Do not seat the screws hard, nice and easy. The low speed circuit should give enough gas to idle and not bog when giving it gas. If a couple turns out is not enough to get it started open in 1/4 to 1/2 turn increments. The high speed should give enough fuel so it does not bog under load so get yourself a log you can do some cuts in. It takes some playing. You may have set the low speed a and idle screw a couple times. Personally I err on the fat side w/ the high speed screw.