Carburetor cleaning with Ultrasonic Tank - Sterwins PHT25 4CC 55 CM

A flathead screwdriver

A Phillips head screwdriver

A T25 torx wrench

A Carburetor Adjusting Hex Screwdriver

Unclip the air filter cover.

Extract the air filter.

Filter and carburetor case fixing screws

In an anticlockwise movement, unscrew the two fixing screws using a T25 torx key.

Remove the two screws and then the filter case.

Remove the carburetor.

Unhook the accelerator cable. Make sure to remember the location.

Extract the transparent fuel return hose.

Extract the black fuel inlet hose.

Unscrew the two priming pump attachment screws by turning them counterclockwise.

Remove the pump.

Peel off the pump membrane.

Once the pump is disassembled, turn the carburetor 180° to access the four mounting screws.

Use a Phillips screwdriver to remove the four membrane cover screws.

Remove the membrane cover.

Remove the needle lever membrane with the membrane seal.

Note: The membrane lever will act on the needle lever.

Unscrew the screw that holds the needle lever shaft.

CAUTION: Be sure to hold the lever with your thumb to prevent the spring from popping out.

Remove the lever, the spring, and the needle.

Set screw

Unscrew the two adjustment screws counterclockwise using the specific adjustment screwdriver.

Extract the two screws.

Immerse the carburetor in the ultrasonic bath for 15 to 20 minutes at a temperature between 25 and 35°.

Remove the carburetor from the ultrasonic bath.

Rinse the carburetor with water, dry it by blowing it out with compressed air.

Reinstall the spring and needle.

Use a flat screwdriver to hold the lever in place.

Tighten the screw that holds the axis of the lever using a Phillips screwdriver.

Reinstall the needle lever membrane and the membrane gasket

Reinstall the membrane cover.

Tighten the four cover fixing screws using a Phillips screwdriver in a clockwise direction.

Reinsert the two adjustment screws.

Screw them in as far as they will go without forcing them clockwise with the adjustment screwdriver.

Pre-adjust the carburettor by unscrewing the two screws one and a half turns counter-clockwise

Take the pump cover.

Reposition the pump membrane and its seal.

Replace the pump cover and tighten the two fixing screws clockwise using a Phillips screwdriver.

Reinstall the black fuel inlet hose.

Reinstall the transparent fuel return hose.

Reattach the throttle cable.

Insert the two fixing screws in the air filter housing and then in the carburetor body.

ATTENTION: Make sure that the fixing screws align with the holes of the gasket.

Tighten the fixing screws clockwise using the T25 Torx key.

Refit the air filter.

Reclips the filter cover.