The correct carburetor adjustment will allow the saw to produce maximum power, extend the duty cycle of the engine, produce minimal smoke, idle smoothly, rev up nicely and give trouble free service. High Speed Fuel Adjustment – This is the adjustment that controls the proportion of fuel in the combustible air/fuel mixture at cutting speed. 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.
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.
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. If you adjust your saw with a dirty air filter, the saw will run too lean when the filter is cleaned. If proper adjustment for your saw is outside the limited range, take your saw into a shop.
Determine the carburetor type before adjusting the high- and low-speed screws. To do this, turn the “L” screw clockwise as far as it will go, using a flat-head screwdriver, then turn it counterclockwise as far as it will go. If it turns more than one complete revolution, it’s a type A carburetor, and if it turns less than one revolution, it’s a type B carburetor.
how do you adjust a chainsaw high low Related Question:
How do you adjust a high and low carburetor?
Step 1. Locate the two fuel-adjustment screws on the side of the carburetor. One will be labeled “Hi” and the other “Lo.” The “Hi” screw regulates the engine at full throttle and the “Lo” regulates the fuel when the engine is idling.
What does L and H mean on chainsaw?
The letters on the screws represent High (H), Low (L) and Idle (T). The H screw regulates the Air/Fuel mix during high RPMs, while the L Screw does the same during low RPMs.
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.
How do you adjust the high and low on a Stihl chainsaw?
Look for the carburetor adjustment screws either near the air filter or under the spark plug. There are three of them, marked “H,” “L” and “I” or “LA,” depending on the model. They are the high-speed, low-speed and idle adjustments respectively.
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.
Why does my chainsaw keep cutting out?
The main culprit behind a chainsaw engine that keeps cutting out is usually a dirty or wrongly adjusted carburetor. A faulty carburetor fails to supply the correct air-fuel mixture, also called the “charge”, to the engine. Causing the engine to cut out or stall.
What does the LA screw on a carburetor do?
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. On Stihl models with adjustable carburetors, the LA screw is accompanied by the L and H screws. These screws adjust the engine’s output at low and high speeds.
Why does a chainsaw cut crooked?
One major reason a chainsaw curves to either the right or left during a cut is that it was unevenly sharpened. The unequal teeth of the chain cause it to take a different-sized bite into the wood. What is this? The uneven sharpness of the chain is mainly due to manual sharpening, especially with the use of a file.
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.
Why does my Stihl chainsaw bog down?
Stihl carburetors have three adjustment screws. One controls the fuel mixture when the engine is idling, one controls it when the engine is operating at low speed and one is for high-speed fuel control. When the saw bogs down during cutting, it’s usually the high-speed screw you need to adjust.
How do you adjust H and L screws on a carburetor?
Set the idle speed screw(not L or H) so it is just able to idle by itself. This screw will have a “stop” it rests against. Now turn the L screw out until in decreases in rpm and then back in(very slowly) until it is at peak rpm. Adjust the H screw once more as above and it should be a very serviceable 2 stroke.
How do you start a stubborn chainsaw?
Try to start the chainsaw after priming the carburetor. 5. Activate the choke by moving the lever to the full choke position and pull the starter rope 3 or 4 times to start the engine. If that doesn’t work, move the choke lever to half choke and pull the starter rope, 6 times maximum, to start the engine.
What is choke on a saw?
The choke position is the fourth setting on the master control lever. This setting is used to start the saw when its motor is cold. Stihl chainsaws denote the choke position using a nearly horizontal squiggle between two vertical lines at the lowest position on the master control lever.
Will a chainsaw run without a fuel filter?
While it’s possible to run your chainsaw without a fuel filter, but this is not recommended. When a fuel filter is clogged, it can cause considerable damage to the engine and leave your chainsaw unusable.