Carburetor “Stihl Mm 55” Shoe.

Cleaning the carburetor 2-stroke engine Stihl MM 55

If you need advice on professional cleaning of the carburetor Stihl MM 55, read the content of this article. In it, you will learn how to clean the carburetor of a two-stroke engine, and under what circumstances you may need to clean it. Cleaning a small engine carburetor is usually done when the carburetor is restored, but there are several reasons why you may only need to clean it.
Proper cleaning of the carburetor two-stroke engine involves complete disassembly and assembly of the device. The following steps explain how to disassemble, clean properly, and assemble the carburetor of a two-stroke Stihl MM 55 engine.

Tip! There are many small details in the carburetor. Keep the parts in the right order for you to assemble quickly and accurately.

  • Remove the bottom cover.

Unscrew the two screws that secure the bottom cover to the carburetor body. On some models, the bottom cover is fastened with four screws.

  • Remove the diaphragm and diaphragm gasket and separate them if necessary.
  • Remove the needle valve mechanism.

The needle valve mechanism consists of three parts: a needle, a lever, and a spring. It will be visible after the extraction of the diaphragm.
The needle valve mechanism holds a screw. Unscrew the needle valve screw to remove the mechanism from the carburetor body.
Make sure the spring stays in place after you remove the screw. It can fly out, and you lose a few essential parts of the valve with it.
Do not forget to fold the carburetor parts in order during disassembly.

  • Disconnect the primer and its retaining plate.
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The primer holds in the case a plate screwed with two screws. Unscrew the two screws that hold the plate.

  • Squeeze the primer out of the plate.
  • Remove the primer base and carburetor plate valve.

Set it aside for cleaning. Look at the thin plate valve between the base of the primer and the carburetor body. Disconnect it carefully: it is essential for the proper operation of the device and requires careful handling. If you damage it, then most likely you will have to change the whole carburetor completely.
That’s all! You have entirely disassembled a two-stroke carburetor engine, and all parts of this device are now ready for cleaning.

To clean your carburetor, you need the following:

  • capacity
  • carburetor cleaning fluid
  • towel
  • compressed air (optional)

The cleaning procedure for each part of the carburetor is about the same and consists of the same type of steps:

  1. Clean the outside.
  2. Clean the inside.
  3. Dry the parts.
  4. Be very careful with sensitive parts.
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Start with the body carburetor Stihl MM 55 and do not be afraid to use a lot of cleaners.

  • Clean all openings in the housing and the paths through which fuel passes.
  • Dry the case thoroughly with compressed air (if present) and lay it on a towel to continue drying.
  • Go to other parts of the carburetor.

The inner holes of the primer require cleaning, as well as the holes on the body of the carburetor.
Cleaning fragile carburetor parts:
Several parts of the carburetor need additional consideration and specific cleaning, including a plate valve, a strainer on the body, and a diaphragm.
Plate valve should be cleaned very carefully. Use smaller cleaning pad to prevent damage to parts.

  • Quickly dry the flap and place on a clean towel.
    Many carburetor designs include a small mesh filter on the body. This filter is easily damaged when removed. It is better to leave it in place if there are no replaceable filters.
  1. Return the needle to the needle valve. The needle valve has a split shape. The top of the needle should go into the forked part of the valve
  2. Replace the needle valve spring. Place the spring back into its slot in the carburetor body.
  3. Insert the needle into the jet valve. The needle valve lever will remain at the top of the spring, while the needle will enter its intended place.
  4. Install needle valve screws.
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Hold the needle valve mechanism in place with your finger and tighten the screw.
This guide for disassembling, cleaning and assembling a carburetor two-stroke engine ends. Follow the steps above, and you will succeed.