As the heart of your chainsaw, the carburetor determines the cutting performance that is related to your work efficiency and cost. This blog covers all the details your need including how to tune the three adjustment screws (the low speed screw, the high speed screw, and the idle screw), what roles do the bar, the chain, the air filter, and the limiter caps play, and how these things affect your adjustment.

Preparation

Before adjustment, you need to keep your guide bar and chain on with proper tension, and a clean air filter as well. Because the lack of any of them will influence how your carburetor reacts when you are tuning. It is also important to warm your chainsaw up for a minute.
Ensure you are in a well-ventilated area, outside or inside, with all doors and windows opened.
You can not just use a regular old screwdriver like we always used to, but a set of specialty fittings, HIPA Repair Kit, will really facilitate your work.

Three Adjustment Screws

The Low Speed Screw

The low speed screw controls the fuel-air mixture and the trigger response of the accelerator.

The High Speed Screw

The high speed RPM (Revolutions Per Minute) is determined by how much you screw it: the more you screw in, the faster the chainsaw runs, and the more you unscrew it, the slower the chainsaw runs.

The Idle Screw

The idle screw is used for adjusting the idle speed of the engine.

Operation

Step 1

You should screw the idle screw in until your chain starts to move.

Step 2

Turn to tune your low speed screw in and out. The low speed screw is always closest to the engine and furthest away from your air filter.
You will find that when you start turning the screw in, the RPM starts to drop if you turn it too far, and comes back to high if you turn it back. And if you keep turning it, the RPM starts to drop again.
So there are two turning points on the low speed screw, and what you need to do is to find the middle point or the sweet point where the engine is idling the fastest. Turn the low speed screw very carefully until you just hear the RPM starts to come back down, then leave it there.
You will get a good trigger response after you finish the step.

Step 3

Turn your idle screw back down until the chain stops moving.

Step 4

Finally, you are supposed to tune the high speed screw. The problem is that the chainsaw will run faster and faster and faster until you blow your chainsaw apart as you screw the high speed screw in all the time. If there is a limiter cap on your high speed screw, you can trust the cap to prevent you from screwing it too much to fire the engine up.
You need to screw the high speed screw in until the limiter cap stops you screwing further. If there is no limiter cap, you can seek help from Google, asking Google what your original settings are for the high speed adjustment screw on the model of your chainsaw.

Product Recommendation

1. HIPA 2-Stroke Carburetor Adjustment Kit