A two cycle engine is an engine that has a complete power cycle in the two piston strokes, namely the upper stroke and the down stroke. The upper cycle compresses the fuel mixture and ignites it at the stroke top. It is exhausted when the down stroke begins. A new fuel mixture gets introduced at the bottom of the down stroke into the cylinder and the cycle begins all over again.
A 2-cycle carburetor tends to be common in small engines popular in homes and gardens as well as recreational equipment segments. You will find these carburetors in snowmobiles, boat motors, lawn trimmers that are gas powered and chainsaws among others. The engines have fewer moving parts, making them much lighter compared to 4-stroke engines. But, why should the carburetor be adjusted?
· Carburetor adjustment is very important because over the time the screws get loose.
· Fuel mixtures also make slight changes to the trimmer head. Considering that the settings of the carburetor affect trimmer performance, the right adjustments need to be made to perfect the performance.
· The adjustment is necessary when there is a carburetor replacement or an installation of a rebuild kit or if the engine does not seem to run effectively any more.
· The adjustment ensures a smooth running of the engine and it should also be coupled with cleaning because a clogged air filter and deposits within the carburetor could also greatly affect the performance of the engine.
Contrary to what many people might think, the adjustment is not that hard. It sure might seem challenging at first, but using the right carburetor adjustment tool, you will not need a mechanic or an engine expert to do the work for you. You can get the special carb adjusting tool for your Poulan, Craftsman, Zama, Weedeater and Husqvarana engines from reputable sites. The adjustment tool is not that hard to use and therefore using a few guiding steps you will manage to adjust the carburetor and have your engine running as smoothly and efficiently as it really should. Here is how you can adjust your 2 cycle carburetor:
Step 1 – Identity the high speed and idle screws on the carb. They are labeled H and L so this should really not be hard for you to identify. You will also see the third screw marked T and this is the throttle screw which determines how fast the unit idles when the carb has been adjusted.
Step 2 – Ensure that the H and L screws are completely closed before you then open them two turns each using your carburetor adjustment tool.
Step 3 – Crank the motor and let the unit warm up, then turn the choke lever to have the unit running. You might need to open the unit by depressing the throttle.
Step 4 – With the unit idling by itself, slowly turn the idle screw in till your unit starts dying, then stop the turning and back the screw out at least to a quarter or half turn to the suitable position.
Step 5 – Holding the throttle wide open, slowly start turning the high speed screw in until you can hear your engine beginning to smoothen out and to rev high. Back the screw out again when the engine starts pitching until the unit starts slowing down or running rough. Let the high speed screw remain in the middle of the high and low point you have found. You can easily tell the best point by being keen on where the unit runs smoothly.
Step 6 – After you have set the operating speed of your 2 cycle engine, allow the engine to go back idle. If there is smooth idling without any stumble or stall, then your adjustment has been a success. If there is a stumbling of the engine, then you might need to continue with the adjustments until you get a smooth idle. The engine should not feel like it will stall and neither should the idle feel like its racing; find a smooth balance.
Adjusting a 2 cycle carburetor can be frustrating in the beginning and it might take a little while to perfect. It is therefore advisable that you take things slow and restart the process until you finally get it right. For your safety when adjusting the carburetor, ensure that you wear protective gear, which can include a long sleeve shirt, safety glasses, leather gloves, closed toe shoes and long pants. Ensure that you are also using the right and high quality adjustment tool for the task.