Adjust stihl carb

Adjust stihl carb DEFAULT

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

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
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How to Adjust the Carburetor on a Stihl Weed Eater

  1. Turn the high-speed screw, marked 'H' counterclockwise until it stops.
  2. Tighten the 'L' screw all the way, then turn it one turn counterclockwise to open it.
  3. Start up the engine and allow it to warm up. The cutting tool will rotate.
  4. Press the trigger of the machine to rev the engine.

Click to see full answer


Considering this, what is the H and L on a carburetor?

On every saw the "h" means that's the "high" side adjustment. It regulates how much fuel is being poured into the motor during high rpm's. The "L" means that's the "low" side adjustment.

Also Know, how do you adjust the H and L on a chainsaw? Carburetor Adjustment Procedure

  1. Before you start the saw, locate a small flat-bladed screwdriver.
  2. Begin by checking the saw's air filter.
  3. Check the fuel level.
  4. Start the engine and warm it up.
  5. Begin by setting the idle speed.
  6. Set the low speed fuel adjustment.
  7. Go back to step (4) and reset the idle speed.

Likewise, what is the LA screw on a Stihl chainsaw?

The LA setting on Stihl chainsaws is controlled by a screw on the outer housing of the engine that adjusts the flow of fuel and air through the carburetor. This screw is inside the engine housing on the carburetor, but is accessible through a hole or gap in the outer housing of the saw.

How do you start a chainsaw that won't start?

To solve this problem, open the spark plug hole with it facing away from you to drain all the fuel in the tank. Deactivate the choke by pushing in the control then pull the starter cord 6-8 times as you press in the throttle control. Dry off the spark plug and refit it back in place.

Sours: https://findanyanswer.com/how-do-you-set-up-a-stihl-carburetor

How to Adjust the Carburetor on a Stihl 066 Chainsaw

  • Place the Stihl 066 chainsaw on the ground and start it as you would normally. Allow the engine to warm up for five minutes before attempting any carburetor adjustments. Locate the carburetor adjustment screws on the back of the chainsaw. There are three screws. One with "H' stamp, one with a "L" stamp and one with an "LA" stamp.

  • Turn the "LA" screw clockwise with a flat-head screwdriver just until the chain begins to rotate on the chainbar. Turn the screw counterclockwise until the chain stops moving. This is the idle and the chainsaw should stay at this speed without sputtering or the chain moving.

  • Adjust the "L" low speed screw clockwise with the screwdriver until the engine begins to make a low gurgling sound. Turn the screw ¼ turn counterclockwise.

  • Squeeze the trigger on the chainsaw. The throttle should gradually raise the engine speed without hesitation or smoking. Turn the "H" high speed adjustment screw clockwise until the exhaust begins to smoke slightly.

  • Turn the screw counterclockwise until the engine begins to sputter while under full throttle. Turn the screw to the midway point between sputtering and exhaust smoke. Readjust the idle if necessary.

  • Sours: https://homesteady.com/how-7570607-adjust-carburetor-stihl-066-chainsaw.html

    Stihl carb adjust

    Stihl 034 Carb Adjustments

    All the above advice is really good advice. I know I can't get a saw adjusted until it starts getting into the wood. I usually start with factory one turn on each, and yes, absolutely turn the idle up a little, like said, so it doesn't continually stall which happens sometimes. Get her warmed up, drop the idle until the chain stops spinning, or turn up until chain spins, then back off until it doesn't, assuming your clutch is in good working order.... then get a feel for how it walks off the low end. If it stumbles like it wants to stall before throttling up, from my experience it's a little fat on the low. If there's fuel spitting out the muffler or misting, or excessive smoke after a break in, too fat. Once the low end feels like it has good response and is sharp and quick, check the high end. Also, feel the saw for heat. Excessive heat, or warmer than what feels comfortable, is an indication of too lean. Cut with it for a little bit, and adjust as necessary, but just keep in mind that an 1/8 of a turn is a lot on these zamas and Walbros. I use a digital tach as well, wrapped on the spark plug. I love them. You can look in the manual and get factory idle and high r.p.m, and dial it if your saw is stock really fast.

    With the 034 and 036, I have not had any saws I can recall that were past 1 1/4 on the turns, unless I m.m.

    One thing I have seen more than once: make sure that pulse line is on. (They can slip off easy in these models)

    Also, if it seems to stall excessively, take the pulse line off and check the plastic nipple on the tank side. I have had quite a few that had a hairline crack on that nipple, and it raises hell with em, and can even blow up a top end.

    Sorry, for the long reply, I just love these models. My tree crews prefer the 036 over the newer saws for general cutting, limbing, etc.. for a mid range saw, they really are hard to beat. Light and powerful, strong and when tunes right they go all day without issue!

     

    Sours: https://www.arboristsite.com/threads/stihl-034-carb-adjustments.306851/
    Stihl FS 94 R Line Trimmer Carburetor Adjustment

    Stihl Chainsaw Carburetor Adjustment

    All Stihl chainsaws have just three carburetor adjustment screws, so fairly easy to work on when you need to a Stihl Chainsaw Carburetor adjustment.

    (LA) Idle Speed screw – This controls the engine speed at idle. If set too low, the saw will die. If set too high the chain will run. This is dangerous.

    (L) Low speed adjustment screw – This is the low speed jet. This is the adjustment that controls the air/fuel mixture at idle. Adjust this screw too rich and the chainsaw will blubber and die at idle speed. Adjust this screw too lean and the engine will starve. The saw will race or surge. An extremely lean adjustment will also cause the engine to die.

    (H) High speed adjustment screw – This is the high speed jet. This is the adjustment that controls the air/fuel mixture at high RPMs. Adjust this screw too rich and the chainsaw will blubber, too lean and it will over rev.

    Safe Basic Settings

    Screws (H) & (L) – Turn the adjustment Screws (H) & (L) down onto their seats (clockwise). Back them off 1 complete turn (counter-clockwise)
    Screw (LA) – Turn (LA) Idle Speed screw until the chain stops. Then turn counter-clockwise one quarter of a turn.

    Fine Tuning – Screw (L)

    Erratic idling behavior; poor acceleration – Idle setting too lean; turn low speed adjusting screw (L) counterclockwise until engine runs and accelerates smoothly. Readjust screw (LA).

    Exhaust smokes at idle speed –Idle speed setting too rich; turn low speed adjusting screw (L) clockwise until engine speed drops. Then turn screw back one quarter turn and check that engine still accelerates smoothly when you open the throttle. Readjust screw (LA).

    Sours: https://chainsaw-workshop-manual.com/how-to-adjust-a-stihl-chainsaw-carburetor/

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