Replacing Stihl Km90r Fuel Filter: Step-By-Step Guide

The Stihl KM 90 R is a powerful and versatile tool, but like any machine, it requires regular maintenance to keep it in top condition. One such task is replacing the fuel filter, which can be done by following these steps:

1. Switch off the engine and allow it to cool down.

2. Remove the fuel tank cap and set it aside.

3. Locate the fuel filter, which is usually found inside the fuel tank.

4. Disconnect the fuel lines from the carburetor ports and remove the old fuel filter.

5. Clean the area around the fuel filter to remove any dirt or debris.

6. Install the new fuel filter by connecting it to the fuel lines and ensuring it is secure.

7. Reattach the fuel tank cap and close the fuel tank.

8. Check the air filter and replace it if necessary.

9. Adjust the throttle cable if needed, following the instructions in the user manual.

10. Start the machine and let it warm up, then adjust the idle speed screw as required.

By following these steps, you can ensure your Stihl KM 90 R runs efficiently and safely.

Removing the old filter

To remove the old fuel filter from your Stihl KM90R, start by turning the choke knob to the 'off' position. Then, take out the screw and remove the filter cover.

Now, you need to remove the old filter. Grip the filter element at the cutout in the filter housing and pull it out. You can knock it out onto the palm of your hand or blow it out with compressed air, but do not wash it.

Once the old filter is removed, you can fit a new one. Simply install the new filter element into the filter housing and fit the cover. Insert the screw and tighten it down.

Make sure to dispose of the old filter properly and recycle it if possible.

Cleaning the air filter housing

To clean the air filter housing on your Stihl KM 90 R, follow these steps:

Firstly, turn the choke knob to the 'off' position. Then, take out the screw and remove the filter cover. Clean away any loose dirt from around the filter housing. Next, grip the filter element at the cutout in the filter housing and remove it. You can knock it out on the palm of your hand or blow it out with compressed air.

Now, you can fit a new filter element. Alternatively, you can reuse the old one if it is still in good condition. Make sure to install the filter element securely in the filter housing, and then fit the cover. Insert the screw and tighten it down.

It is important to keep your air filter clean to ensure optimal engine performance and prolong the life of your Stihl KM 90 R. Regularly check your air filter and clean or replace it when necessary.

Installing the new filter

To install the new filter, follow these steps:

Firstly, ensure that you have removed the old filter and cleaned away any loose dirt from around the filter housing. Grip the old filter element at the cutout in the filter housing and remove it. Now, take your new filter and install it into the filter housing. It should fit snugly and securely.

Next, fit the cover over the new filter. Insert the screw and tighten it down securely. Do not overtighten the screw, as this may cause damage. With the new filter installed, you can now refill the fuel tank and prepare to restart the machine.

Before restarting, ensure that you have followed the necessary steps to prepare the machine for operation, including checking the air filter, throttle cable adjustment, and spark-arresting screen. These steps are outlined in the Stihl KM 90 R Instruction Manual and should be followed carefully to ensure the optimal performance and safety of your machine.

Once you have completed the above steps, you can start the machine and let the engine warm up. Use the idle speed screw to set the idle speed, ensuring that the working tool does not move. Fine adjustment of the high-speed screw may be necessary, depending on your operating conditions.

Adjusting the carburettor

To adjust the carburettor of your Stihl KM90R, follow these steps:

Firstly, switch off the engine and mount the KombiTool with the attached working or cutting tool. Check the air filter and replace it if necessary. Check the throttle cable adjustment and adjust if needed, as outlined in the "Adjusting the Throttle Cable" section of the instruction manual.

Next, check the spark arresting screen and clean or replace it if required. Now, carefully turn both the high-speed screw (H) and the low-speed screw (L) counterclockwise until they are firmly seated and open by 3/4 of a turn.

Start the machine and let the engine warm up. Using the idle speed screw (LA), adjust the idle speed so that the working tool does not move.

Finally, a fine adjustment of the high-speed screw (H) may be required if the engine performance is not satisfactory in certain conditions, such as high altitude or sea level, or after changing working tools.

Please note that the carburettor settings can only be adjusted within narrow limits, as it has been designed for optimum performance and fuel efficiency in all operating states.

Checking the spark arresting screen

To check the spark arresting screen on your Stihl KM90R, follow these steps:

Firstly, wait for the muffler to cool down. Then, move the slide control to STOP-0. Take out the screw (1) and then remove the screws (2) and take off the muffler cover (3). Now, take out the screw (4).

You can now lift the spark arresting screen (5). Check the screen for any damage or carbon build-up. If the screen is damaged or heavily carbonized, you will need to fit a new one. If it is simply dirty, clean it.

Once you have cleaned or replaced the screen, refit it and insert the screw (4) and tighten it down. Now, insert the screws (2) and refit the muffler cover (3). Finally, insert the screw (1) and tighten it down.

It is important to check the spark arresting screen if your engine is down on power, difficult to start, or running poorly at idling speed. A dirty spark arresting screen can be one of several factors that cause deposits to form on the insulator nose of the spark plug, leading to operational issues.

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