If you have a new saw, this won’t apply to you, as new regulations require saws to be built so that only a qualified technician can tune the carburetor. If you have an older saw, here’s how to quickly tune it yourself. Less than five minutes of your time can make a big difference in how well your saw runs.
Adjusting the H screw clockwise increases the maximum speed of the engine and can cause damage to your saw’s engine if its operating capacity is exceeded. L Screw – With the chainsaw still running, take a screwdriver and turn the L screw clockwise. If you believe fuel has flooded the chainsaw engine, pull the starter cord several times while holding the throttle, dry and replace the spark plug, and then try starting the chainsaw again.
It regulates how much fuel is being poured into the motor during high rpm’s. The more you tighten them the less fuel that goes in on that particular part of the rpm range. The more you loosen them the more fuel gets dumped in on that rpm range.
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. Small adjustments to the L, H and LA screws can have a major impact on how your chainsaw runs. On many models of Stihl chainsaws, the L and H screws are marked, but the LA screw is not.
what does the l and h mean on a chainsaw Related Question:
What is the LA setting on 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.
What do the H and L screws do on a carburetor?
This adjustment controls the fuel flow to the low speed or idle circuit. If the carburetor is too far out of adjustment to run, or has been disassembled, start with turning the L and H all the way in and then open 2 turns on each needle.
What is H and LA on Stihl chainsaw?
One marked “H”, for high speed, one marked “L”, for low speed and one marked “LA”, which is your low speed air adjustment for idle.
Why does my chainsaw bog down when I give it gas?
If your chainsaw is bogging down when you give it throttle, this is often a sign of improper gas-to-oil ratio. If there is too much gasoline in relation to the amount of oil used, this is known as a “rich mixture” and can cause the chainsaw to run poorly.
What is the T adjustment on chainsaw?
The T screw regulates how much fuel is sent to the carburettor while idling until the throttle is pressed. L Screw – With the chainsaw still running, take a screwdriver and turn the L screw clockwise. Keep turning it until the engine almost stops turning.
What are the 2 screws on carburetor?
There should be two screws on the front of the carburetor, which are used to adjust the air and fuel mixture. Often these look like flat-head screws and you can use a screwdriver to turn them, adjusting the amount of fuel and air mixing in the carb.
Why does my chainsaw only runs on choke?
When your chainsaw only runs if the choke is on the problem, in most cases, is a result of fuel supply problems or a faulty carburetor. To fix the problem you should check and clean the fuel system and carburator.
How do you adjust a Stihl carburetor?
Start the trimmer and hold the throttle trigger in all the way to get the trimmer head spinning at maximum speed. Turn the H screw clockwise with a carburetor adjustment tool until the head is spinning as fast as it will go, then back off the screw carefully until the RPMs start to decrease.
What does a spark arrestor do on a chainsaw?
The spark arrestor on your chainsaw prevents dangerous hot sparks from igniting fires while you’re working. If the arrestor is clogged or dirty, however, it will also prevent exhaust from leaving the motor, which can prevent it from running.
Why does my chainsaw bog down when I pull the trigger?
The reason for that may be you’re using the saw at altitude or the carburetor adjustment has simply slipped. The saw also won’t operate well at speed if the air filter or spark arrestor or carburetor are dirty.
Why does my chainsaw cut out after starting?
A clogged carburetor is often caused by leaving fuel in the chainsaw for a long period of time. Over time, some of the ingredients in the fuel may evaporate, leaving behind a thicker, stickier substance. This sticky fuel can clog up the carburetor and cause the chainsaw engine to stall.
Why does my chainsaw rev too high?
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.
Why is my chainsaw idling high?
The most probable – and easiest to fix – cause of chain rotation while the chainsaw engine idles is a poorly adjusted idle setting on the carburetor. The result is that too much fuel is delivered to the combustion chamber when the throttle is released, and the engine doesn’t really slow.
How do I set my carburetor to use less fuel?
Once the engine has arrived at operating temperature, go back to the carburetor and adjust the air fuel mixture screw, or screws. Tightening the screw increases the amount of fuel, while loosening decreases the amount of fuel.
Which way do you turn a mixture screw?
On most carburetors, turning the mixture screw in (clockwise) leans the mixture, while counterclockwise (out) enriches the mixture. Initially, if the engine stumbles or the vacuum drops when turning the mixture screw in, turn both screws out about a -turn and evaluate the results.