Carburetor Top Removal

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Removing the top of the carburetor is relatively easy, and is the key to setting the float level. Almost all repairs can be done by partially disassembling the carburetor, meaning take the top off. Be sure to use a large enough screwdrive to avoid damaging the screws. Do not overtighten.

Take the Top Off

Note that the top gasket is not a critical piece. On downdraft, there is only one vacuum passage. The rest of the top gasket is mostly there to seal the carb from dirt, and to prevent vapors from escaping (air pollution).

The carburetor will run fine with a partially torn top gasket as long as it seals around the center hole (for downdraft type).

A new gasket comes with a carburetor repair kit.

Hitachi DCx series

The hardest part is disconnecting the throttle pump linkage on the outside of the carb. This is the long lever along the top of the carb and a connecting rod that connect the throttle to the pump. There are also small clips that hold the levers.

Be careful and don't lose these small parts

1. remove choke linkage cotter pin
2. remove pump lever bolt. Note how the spring goes

   Be carefull not to drop the flat washer and lock washer

   

3. remove and plug Fuel Line
4. auto choke models: remove choke pull-off hose

   

5. auto choke models: remove the two large screw under the choke housing

   This is the hardest part of the whole job

6. remove the top screws
7. carefully lift the top straight up a small amount. Check the gasket.
8. If needed, pry the gasket from either the top or the body, so it stays in one piece
9. remove top completely. The float comes out with the top, so carefully guide it past the edges of the gasket

Hitachi Twin Carb

For Hitachi Twin Carb, the float bowl top is held on by four screws.

1. remove fuel inlet line
2. remove fuel overflow line (vent line on newer versions)
3. remove the four screws
4. carefully lift the top up a small amount. Check the gasket.
5. If needed, pry the gasket from either the top or the body, so it stays in one piece
6. remove top completely. The float stays in the bowl

Re-assembly

Put the top back on in reversal of the steps above.

CAUTION: Tighten the bolts only enough to compress 
the lock washers, no more.

Lay the gasket on the carburetor body. Carefully push the Accelerator Pump though the gasket, also guide the Float pin past the edges of the gasket.