Stihl 044 carburetor adjustment

Stihl 044 carburetor adjustment DEFAULT

Carburetor Adjustment On Pro Saws

Carburetor

All saws occasionally need to have their carburetor adjusted. A saw with a properly adjusted carburetor will produce maximum power, minimal smoke, run and idle smoothly, and give trouble free service. A saw that is too rich will produce excessive smoke and have insufficient power. A saw that is adjusted too lean will also have insufficient power, but this condition can quickly cause engine damage. The following information outlines the process of adjusting a carburetor on a pro saw.

Most Pro Saw Engines Have Three Carburetor Adjusting Screws:
  1. Idle Speed/Throttle Stop - This is the adjustment that controls how much the throttle valve (butterfly) stays open when the throttle trigger is released. If this adjustment is set too low, the engine will die when the throttle trigger is released. If this adjustment is set too high, the high idle speed will cause the centrifugal clutch to engage and the chain will run. This is a dangerous condition.
  2. Low Speed Fuel Adjustment - This is the adjustment that controls the proportion of fuel in the air/fuel mixture at idle speed. An adjustment that is too rich will cause the engine to load up and die at idle speed. A mixture that is too lean will starve the engine and cause it to race or surge. An extremely lean adjustment will cause the engine to die, too.
  3. High Speed Fuel Adjustment - This is the adjustment that controls the proportion of fuel in the air/fuel mixture at cutting speed. It would not be accurate to say this is the most important setting, because all of these adjustments need to be accurate for a saw to perform its best, but this is the adjustment that determines how the saw runs in the cut. An adjustment that is set too rich will not allow the saw to reach the RPM level necessary to build maximum power. Throttle response may also be sluggish and the engine will smoke and perform poorly. A mixture that is too lean will allow the engine to reach an RPM level where bearing failure and cylinder seizure are likely. It will also lack power in the cut and tend to run very hot.
Rich Running Conditions

An over rich carburetor adjustment is when the proportion of fuel in the air/fuel mixture is too high. When this occurs,  the fuel does not burn well. What does burn, does not produce much heat, so the power stroke is weak. The partially burned mixture is expelled into the muffler and exits the saw as smoke. An over rich condition also causes carbon buildup. 

Lean Running Conditions

A lean carburetor adjustment is when the proportion of fuel in the combustible air/fuel mixture is so low that there is not enough fuel to burn. This also makes a weak power stroke and causes the saw to have insufficient power. In addition to low power, a lean condition causes the cylinder temperature to rise, which can  lead to a seizure. A lean condition also allows for excessive RPM, causing rod bearing failure.

Blocked exhaust port

It is best to use a digital tachometer when adjusting the carburetor on a pro saw. These tachs are easy to use and require no wires. When the tach is placed near the spark plug, it picks up an electrical signal when the plug fires. On a two-cycle engine, this occurs every engine rotation, so the tachometer simply counts the pulses and displays the results.

Carburetor Adjustment Procedure

  1. Before you start the saw, locate a small flat-bladed screwdriver. The screwdriver needs to be small enough to fit through any adjustment hole. Make sure the holes are free from debris and the ends of the adjustment screws are visible. On some saws, these areas can pack with chips, making adjustment difficult or impossible.

    You're also going to need a tachometer. It is difficult (for even a trained ear) to adjust today's saws as accurately as is necessary without a tach. We have adjusted thousands of saws and we use a tachometer religiously.
  2. Begin by checking the saw's air filter. Clean it if necessary. Adjusting the carburetor with the air filter partially clogged is like adjusting the carburetor with the choke partially on. If you adjust your saw with a dirty air filter, the saw will run too lean when the filter is cleaned. 
  3. Check the fuel level. The tank should be over half full. If the carburetor is adjusted when the fuel tank is nearly empty, the carburetor may be adjusted too rich when the fuel tank is filled.
  4. Start the engine and warm it up. Carburetor adjustments made on a cold engine will be too rich when it reaches normal operating temperature.
  5. Begin by setting the idle speed. Try to set the speed at about 2700 RPM. If you don't have a tachometer, try to set the speed so the saw will idle with the chain stopped. Never set the idle so the chain runs when the throttle is released. If the saw will not idle, go to the next step.
  6.  Set the low speed fuel adjustment. Slowly turn in the screw until the engine surges or starves for fuel (lean). Make a mental note of the position of the screwdriver slot. Now slowly turn the adjustment screw out and the engine should run better. Keep turning the screw until the engine starts to load up (rich). Make a note of the position of the screwdriver slot and compare it to the position of the lean adjustment. Now slowly turn in the screw to a position where it idles the best. It should be about midway between the rich and lean positions.

    Click on the link below and a WAV sound clip will be loaded into your browser. What you'll hear is an idling saw. Slowly we lean the low speed adjuster until the idle climbs and it then starts to die. Then we go rich and the engine starts to blubber, the RPM's drop, and the engine almost dies. The optimum setting is between these two extremes. 

    These are approximately. 25 seconds long, but require time to load. Those of you with slow systems or connections may not want to wait! Click here for Saw Idle Adjustment Sound WAV
  7. Go back to step (4) and reset the idle speed. Chances are that the RPM setting has changed since you optimized the fuel mixture adjustment.
  8. Set the high speed fuel adjustment. Hold the trigger wide open and check the RPM with the tachometer. The listing below identifies the maximum RPM setting for popular pro saws with bar & chain and no load:
    • STIHL 044, MS440, 046, MS460 - 13,500 RPM
    • STIHL 066, MS660 - 13,000 RPM
    • STIHL 084, 088, MS880 - 11,500 RPM
    • HUSQVARNA 272, 372 - 13,500 RPM
    • HUSQVARNA 288, 385, 390, 394, 395 - 13,000 RPM
    • HUSQVARNA 3120 - 11,500 RPM
    NOTE: If you do not have a tachometer, set the RPM level so that the saw "four cycles" or "blubbers" at wide open throttle. Do not attempt to set at maximum RPM levels without a tachometer. Setting the adjustment slightly rich will diminish performance, but reduce the possibility of damage to the saw engine.
  9. Click on the link below and a WAV sound clip will be loaded into your browser. What you'll hear this time is a saw being adjusted for full speed. After revving it up to max RPM and holding the trigger, we adjust the high speed rich, causing it to slow down and blubber. Then we adjust it lean, causing it to sound smoother, but then it starts to starve for fuel. As we back it off from lean to rich again, the sound becomes slightly rougher. This slightly rough sound (or 4-cycle sound, as it's sometimes referred to) is where you want it to be. We like to say, as "close" to the smooth as you can get it, but still just slightly into the rough.

    This one is larger than the first, and requires more time to load. Those of you with slow systems or connections may not want to wait! Click here for Saw Full Rev Adjustment Sound WAV
  10. Go back to step (4) and fine tune the idle speed adjustment and low speed fuel adjustment. Movement of one adjusting screw often causes the other two to need readjustment.
  11. Your saw is properly adjusted and ready for work.
Why A Carburetor Has To Be Readjusted

If a carb is set right when a saw is new, why does it have to be readjusted? Some people wonder why their saw needs occasional tuning. They don't understand why saws can't be set at the factory and stay correctly adjusted for the life of the saw. The reason is there are many operational changes a user makes without realizing it. These changes include working at different elevations, changes in fuel, and a host of other factors cause saws to need periodic carburetor adjustment.

Today, sophisticated electronics can monitor and meter air/fuel needs. With this technology, saws will be able to "self adjust." This technology is well developed for automobiles and trucks. The process of miniaturizing an economical and durable system that will work on a saw engine is being developed. Until then, keep your tachometer and screwdriver handy.

Our Advice

The preceding information briefly explains rich and lean running conditions. It also identifies the three adjustment screws and their function. It should be noted that on today's pro saws, most of these adjustments have "limiters" that limit the range of carburetor adjustment. In most cases, proper adjustment is within this range, but not always. If proper adjustment for your saw is outside the limited range, take your saw into a shop. Sometimes this is caused by a problem with your saw, and sometimes the range on the limiters just needs to be reset.

Got questions or comments? Call or stop in.


Sours: http://www.madsens1.com/saw_carb_tune.htm

Stihl Carb Baseline Settings

I don't know them but I think I can get you there.
Turn jets gently CW to lightly seat them.

Do be sure NOT to screw the adjustment needles in tight they will damage easily.

Open both 1 turn CCW from lightly seated.
Turn the LA (idle speed) screw in CCW and then out about half way of it's total travel.
Start the saw let it warm 2-3 min.

Now work on the idle:
Turn the LO screw CCW until it drops slightly.
Note where this point is.
Next turn the screw CW until it drops, note where this point is.
Set the saw midway between the 2 points and a little bit CCW (1/16th turn) to enrich it as bit.

The HI - squeeze the throttle (Never more than 4-5 seconds at a time) and turn the HI screw CCW until the saw goes from a smooth buzz to a raspy exhaust sound.
You want it to sound a little raspy,"burbley", if begins to sound smooth and "buzzy" it's too lean and will damage/overheat the saw.

After you set the HI you may need to tweak the LOW again

Your LA (idle) screw - turn it CW until the chain starts moving at idle. This will be too fast. Now back it out CCW until the chain stops. Then go 1/8 turn CCW.
After you set the LA screw you may need to set the LO again.
These are fussy fine adjustments but you have a fully adjustable carb which is good.

You may need to do this a couple of times to get it right.
Without a tachometer you want the saw to be rich.
This will ensure proper lubrication from the fuel/oil mixture and good cooling. It can be frustrating but take your time.
It's rewarding to tune one correctly.
The link I put here is the "right way" to do this.
Good luck
-br

Here is a link that might be useful: Madsens page for saw tuning. Sounds and explanation.

Sours: https://www.houzz.com/discussions/1619856/stihl-carb-baseline-settings
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Carburetor Adjustment on Pro Saws Info

Carburetor adjustment is critical on chain saws and other two-cycle engines. An adjustment that is too rich will cause a saw to smoke, have insufficient power, and may damage the engine. An adjustment that is too lean will also produce insufficient power and is more likely to damage the engine. Proper carburetor adjustment will allow the saw to produce maximum power, produce minimal smoke, run and idle smoothly, and give trouble free service.

An over rich carburetor adjustment is when the proportion of fuel in the combustible air/fuel mixture is so high that the fuel does not burn well. The burn does not produce much heat, so the power stroke is weak. The partially burned mixture is expelled into the muffler and exits the saw as smoke. An over rich condition causes carbon buildup and will plug the fire screen and cylinder ports if run for a period of time.

A lean carburetor adjustment is when the proportion of fuel in the combustible air/fuel mixture is so low that there is not enough fuel to burn. This also makes a weak power stroke and causes the saw to have insufficient power. In addition to low power, a lean condition causes the cylinder temperature to rise, which often leads to seizure. A lean condition also allows for excessive RPM which often leads to big end rod bearing failure. In our shop we see more premature engine failure caused by lean running conditions than rich ones.

 


Most Chain Saw Engines Have Three Carburetor Adjusting Screws:

1. Idle Speed/Throttle Stop - This is the adjustment that controls how much the throttle valve (butterfly) stays open when the throttle trigger is released. If this adjustment is set too low, the engine will die when the throttle trigger is released. The throttle valve (butterfly) simply cuts off the supply of combustible air/fuel and the engine stops. If this adjustment is set too high, the high idle speed will cause the centrifugal clutch to engage and the chain will run. This is a dangerous condition and should never be allowed.

2. Low Speed Fuel Adjustment - This is the adjustment that controls the proportion of fuel in the combustible air/fuel mixture at idle speed. An adjustment that is set too rich will cause the engine to load up and die at idle speed. A mixture that is too lean will starve the engine and cause it to race or surge. An extremely lean adjustment will cause the engine to die, too.

3. High Speed Fuel Adjustment - This is the adjustment that controls the proportion of fuel in the combustible air/fuel mixture at cutting speed. It would not be accurate to say that this is the most important setting, because all of these adjustments need to be accurate for a saw to perform its best, but this is the adjustment that determines how the saw runs in the cut. An adjustment that is set too rich will not allow the saw to reach the RPM level necessary to build maximum power. Throttle response may also be sluggish and the engine would smoke and perform poorly. A mixture that is too lean will allow the engine to reach an RPM level where bearing failure and cylinder seizure are likely. It will also lack power in the cut and tend to run very hot.

The preceding information briefly explains rich and lean running conditions. It also identifies the three adjustment screws and their function. It should be noted that some chain saws lack the high speed adjustment needle. These saws have what is called a "fixed jet" which is set from the factory. "Fixed jet" carburetors are used to prohibit the saw operator from setting the adjustment too lean and damaging the saw. Unfortunately, they also often prohibit the saw from achieving maximum performance.

 


Carburetor Adjustment Procedure

The following procedure should be followed to insure proper carburetor adjustment:

1. (1) Check the air filter and clean it if necessary. Adjusting the carburetor with the air filter partially clogged is like adjusting the carburetor with the choke partially on. If you adjust your saw with a dirty air filter, the saw will run too lean when the filter is cleaned.

2. (2) If carburetor adjustment is required due to a new or rebuilt carburetor, it is best to start with the fuel adjustment settings one turn out. This is accomplished by gently screwing the adjusting screws onto their seats and then backing them out one turn each. Care must be taken when screwing them onto their seats because the seats may be easily damaged if the adjustment screws are seated too hard. These seats are delicate and if they are damaged, the carburetor has to be replaced.

3. (3) Check the fuel level. The tank should be over half full. If the carburetor is adjusted when the fuel tank is nearly empty, the carburetor may be adjusted too rich when the fuel tank is filled.

4. (4) Start the engine and warm it up. Carburetor adjustments made on a cold engine will be too rich when it reaches normal operating temperature.

5. (5) Begin by setting the idle speed. Try to set the speed at about 2700 RPM. If you don't have a tachometer, try to set the speed so the saw will idle with the chain stopped. Never set the idle so the chain runs when the throttle is released. If the saw will not idle, go to the next step.

6. (6) Set the low speed fuel adjustment. Slowly turn in the screw until the engine surges or starves for fuel. Make a mental note of the position of the screwdriver slot. Now slowly turn the adjustment screw out and the engine should run better. Keep turning the screw until the engine starts to load up. Make a note of the position of the screwdriver slot and compare it to the position of the lean adjustment. Now slowly turn in the screw to a position where it idles the best. It should be about midway between the rich and lean settings.

7. Click on the link below and a WAV sound clip will be loaded into your browser. What you'll hear is a idling saw. Slowly we lean the low speed adjuster till the idle climbs and it then starts to die. Then we go rich and the it starts to blubber and the RPM's drop, almost to a point where it dies. The optimum setting is between these two extremes. If you're adjusted too lean it'll run out of gas and die, or die when accelerated. (Note that a saw adjusted too lean on the high can also die when accelerated.)

8. These are app. 25 seconds long, but require time to load. Those of you with slow systems or connections may not want to wait!

9. Click here for Saw Idle Adjustment Sound WAV

10.  

11. (7) Go back to step (5) and reset the idle speed. Chances are that the RPM setting has changed since you optimized the fuel mixture adjustment.

12. (8) Set the high speed fuel adjustment. Hold the trigger wide open and check the RPM with the tachometer. The listing below identifies the maximum RPM setting for popular pro saws without bar & chain:

· STIHL 044 - 13,500 RPM

· STIHL 066 - 13,000 RPM

· STIHL 084 - 11,500 RPM

· HUSQVARNA 272 - 13,500 RPM

· HUSQVARNA 288 - 13,000 RPM

· HUSQVARNA 394 - 13,000 RPM

· HUSQVARNA 3120 - 11,500 RPM

1. NOTE: If you do not have a tachometer, set the RPM level so that the saw "four cycles" or "blubbers" at wide open throttle. Do not attempt to set at maximum RPM levels without a tachometer. Setting the adjustment slightly rich will diminish performance, but reduce the possibility of damage to the saw engine.

2.  

· Click on the link below and a WAV sound clip will be loaded into your browser. What you'll hear this time is a saw being adjusted for full rev. After revving it up to max RPM and holding, we adjust the high speed rich, causing it to slow down and blubber, developing little power. Then we adjust it lean causing it to sound smoother and then it starts to starve, also creating little power and creating a LOT of heat. As we back it off from lean to rich again, the sound becomes slightly rougher. This slightly rough sound (or 4-cycle sound, as it's sometimes referred to) is where you want it to be. We like to say, as "close" to the smooth as you can get it, but still just slightly into the rough.

· This one is larger than the first, and requires more time to load. Those of you with slow systems or connections may not want to wait!

· Click here for Saw Full Rev Adjustment Sound WAV

·  

· Go back to step (5) and fine tune the idle speed adjustment and low speed fuel adjustment. Correction at one adjusting screw often causes one of the other adjustment screws to need readjustment.

· Your saw is properly adjusted and ready for work.

·  

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2. Why Can't Carbs Be Set When They Are New & Then Leave Them Alone?

3. Some people wonder why their saw can't be adjusted when it's new and then not need any other tuning. They don't understand that saws can't be set at the factory and stay correctly adjusted for the life of the saw. The fact is, some manufacturers think that way, too, and have tried "fixed jet" and "semi-fixed jet" carburetors. These types of carburetors have never worked well. The reason is that elevation, fuel type, and a host of other factors cause saws to need periodic carburetor adjustment. In the future, fuel injection units will probably be developed for chain saws. Sophisticated electronics will be able to monitor and meter air/fuel needs of two-cycle engines and saws will be able to "self adjust." Until then, keep your adjustment screwdriver handy.

4.  


5.  

6. Got questions or comments? Call, stop in, or send us E-mail.

7.  

8. MADSEN'S
SHOP & SUPPLY INC
1408 S. Gold St #2, Centralia, Wa 98531
Phone: 360-736-1336 Fax: 360-736-9522

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Sours: http://www.fairpoint.net/~billyjoejr/chainsaw/Carb_Adjustment_on_Pro_Chainsaws_Info.htm

044 Carb setting/ tune questions.

Stihl make great chainsaws, but the literature is sometimes subpar. There are MANY contradictions that can be found when watching videos or reading shop manuals produced by Stihl. You are correct that some of the carburetor specifications will vary. Sometimes it's because different versions of the carburetor have been released, and other times could be due to typos when translating the original documents from German to English.

Lots of good ideas above, but this suggested method can work well if the saw is in good shape. It's always best to perform vacuum/pressure checks BEFORE doing this. One small leak in an oil or pan seal can ruin an engine when revving to the upper limits. Slow tank vents can also cause catastrophic damage at high speed when ignored. Anything that causes leaning of the fuel/oil mix or slower fuel induction can and will cause some damage when ignored during the tuning process.

There may be nine different carburetors used on this model throughout production. If the number starts with C3M, with about seven versions, get rid of it. This is an outdated model, one of which has an automatic choke. The most recent models are below with the 17a being most recent.

The factory specs are slightly different for the 15b and 17a carburetors, depending on the presence of limiter caps. Begin by removing limiter caps, if present, and adjust the low and high circuits to the factory suggestions. The 15b is one turn for both screws with or without limiters. The 17a is one turn each for no limiters, and 3/4 high 1/4 low when limiters are present. Don't be surprised if the letter varies, as not all model updates are published. The saw must be started and warmed for a few minutes with low revs using 89 octane or higher fresh fuel mix. If the saw is extremely difficult to keep running, vacuum/pressure checks for all components are in order!

Start with the LA screw, and adjust it to 3,300 RPMs. Next, find the optimum point (highest possible speed at idle) on the low circuit. If the engine increases speed significantly when the optimum point is found, use the LA to reduce back to 3,300. Search for the optimum point again on the low circuit, and it should be below 3,700 RPMs before proceeding.

The low circuit needs to be enriched at this point to lower the idle speed to 2,500 RPMs. If this is not possible, a hard fault in the engine or carburetor needs to be identified before continuing!

The high circuit is adjusted next, but it needs to be enriched beyond factory settings to ensure proper cooling and lubrication of the engine components during this portion of the procedure. A lean high setting, fault in the carburetor, or engine leak during this phase will usually toast the piston/cylinder assembly!

Use 'bursts' at WOT to gauge how the engine is accelerating. Start with a few seconds per burst, working up to five seconds maximum during the process. Usage of the EDT 7 will help, as it stores the high speed results in memory. The heat generated during the phase can melt internal components in a split second!

A healthy saw should run below factory specs at this point, which is 13,500 for the 044 during one five second burst at WOT. If not, there may be a leak somewhere! If running behavior seems suddenly erratic, do not proceed without repeating vacuum/pressure diagnostics (I have seen pan seals fail a few times during quality control checks following general repairs).

If the readings are lower than advised, simply lean the high circuit in small increments, repeating a five second WOT burst afterward. On a healthy saw, it will slowly move toward the target speed after each adjustment. If this was my saw, 12, 700 would be a better rate for high speed. It can always be leaned at a later time if the plug appearance or running behavior while cutting suggests the need for adjustment.

This sequence works very well when no other hard faults are present. If the saw doesn't respond as described, full diagnostics are needed to determine the failure.

Install new limiter caps when finished, in case the EPA police inspect your saw.....

 

Sours: https://www.arboristsite.com/threads/044-carb-setting-tune-questions.285813/

044 carburetor adjustment stihl

And it fell off the pipe, it cannot be screwed on already. It is necessary to turn off the water or plug this pipe with something. Let's go. Let's see what happened to you and decide on the spot what we will do. - suggested Kohl.

I blew up my Stihl 044,

People will hear. Take it easy. Enough. Come to me, come. Drink some tea and calm down.

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He brushed his teeth for the third time in an hour. - I'm coming. Hi Karin. Wow.



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