Husqvarna 545, 545 TrioBrake, 550XP, 550XP TrioBrake, 550XPG, and 550XPG Triobrake-Dismantling the carburetor

The Husqvarna 545, 545 TrioBrake, 550XP, 550XP TrioBrake, 550XPG, and 550XPG TrioBrake chainsaws require proper maintenance of their carburetors for optimal performance. If you encounter any issues with the carburetor, the following guide will be useful for dismantling, cleaning, and inspecting it.

A comprehensive Workshop Service Manual containing detailed instructions, diagrams, and additional chainsaw repair information, including dismantling and refitting procedures, is available for download. A brief summary of the guide is provided below.

Husqvarna 545, 545 TrioBrake, 550XP, 550XP TrioBrake, 550XPG, and 550XPG TrioBrake Parts List, Operator Manual, and carburetor manual are also available to view or download as a PDF which can be read on any device or easily printed.

Dismantling the carburetor on The Chainsaw

1. Dismantle the cylinder cover and the air filter

2. Loosen the screws

Screw F. Unhook the rubber attachment G on both sides. See Figure 35.

3. Loosen the suction hose A

The return hose B, and the tank bleeding hose C. See figure 34.

4. Remove the air filter holder

Let the air filter holder remain in place in the cabling for the stop button. Loosen the fuel hose, D. Unhook the throttle cable,

1. See figure 34.

5. NOTE! Press down the lug to release the carburet- tor. Lift out the carburetor

See figure 36.

The lug on the carburetor is securely attached to the partition wall.

6. Use a small flat screwdriver to snap open the connector from the black attachment

Separate the connector by pressing down the catch with a flat screwdriver and then pulling the unit apart. See figure 37.

7. Dismantle the pump cover

Cover pump H and carefully remove the control diaphragm J and gasket K.

8. Unscrew screw P and remove needle valve M with lever arm 0, shaft L and spring R

9. Use a needle or similar device and carefully pull up the fuel screen (W)

See figure 39.

10. If necessary, dismantle the throttle valve

Valve T and choke valve U and air valve S, and remove the shafts with lever arms and springs (see figure 39).

11. If necessary, dismantle the AutoTune AB unit

See figure 39.

Cleaning and inspection

Clean all units in clean petrol.

Use compressed air to dry the petrol on the components. Direct the air through all channels in the carburetor housing and ensure that they are not blocked. Check the following:

1. That the gasket, pump, and control diaphragms are undamaged, as well as the gasket between the carburetor body and the autotuner.
2. That there is no play on the throttle and choke valve shafts.
3. That the needle valve M and its lever arm 0 are not worn. See figure 38.
4. That the fuel screen W is intact and clean. See figure 39.
5. That the inlet manifold V is intact. See figure 39.
6. Use the service tool, Engine Diagnostic Tool 576 69 23-01, to inspect the AutoTune unit. See separate instructions.

Assembly

Observe cleanliness when assembling the carburetor. The slightest contamination can result in downtime.

1. If throttle and choke valves with shafts, lever arms, and springs are removed, these must be assembled. The spring is tensioned 1-2 turns. Lubricate the shaft bearings using a light oil.
2. Fit the fuel screen W using the handle of a small screwdriver. See figure 39.
3. Fit the gasket X in the carburetor as well as the holder Y. Screw in place screw Z as outlined in figure 39.
4. See figure 39 on how to assemble the AutoTune AB unit with gasket.

Note! When replacing the AutoTune unit or carburetor with an AutoTune unit, the unit must first be programmed before it can be used.

Refer to the local support page for more information

1. Assemble needle valve M with lever arm 0, shaft L, and spring R, and tighten screw P. (Fit the expansion washer). See figure 40.

1. Check using a ruler or the like that the lever is level with the assembly plane on the cover.

If necessary, the lever arm can be bent, see figure 41.

1. Fit gasket K, the control membrane J and the pump cover H. See figure 42. Carry out a pressure test.

Read more in the workshop manual, free to view and download from our website.

You can easily access the parts list, operator manual, and carburetor manual for the Husqvarna 545, 545 TrioBrake, 550XP, 550XP TrioBrake, 550XPG, and 550XPG TrioBrake models. These manuals are available for viewing or downloading in PDF format, which can be read on any device or printed for easy reference.