When the engine is running, look at the float glass, make sure the level is right. If it's not within 1 mm of the center line of the glass, you'll need to take the carb apart to adjust the float level. A repair manual will be useful here.
If the float level is OK
If the fuel level is within 1mm of the dot, it is already at the correct adjustment.
IMPORTANT: High fuel pump pressure can cause a high float, so if it is high, perform the Fuel pump pressure test first -- before taking the carb apart to adjust the Float Level.
1. Remove the top of the carburetor. See Carburetor Top Removal for instructions.
Reassembly: Put the top back on in reverse order of dis-assembly. Just tighten the bolts enough to compress the lock washers. No more.
Then perform Idle Speed and Mixture Adjustment - which will change due to changed float level.
|Hitachi 306 Carburetor Articles|
|Diagram - Parts breakdown|
|Specifications - year by year, including Jet specifications|
|Jets & air bleeds (part numbers & locations)|
|Parts general parts|
|Adjustment (normal tuning)|
|Hitachi 306 Photo Index|
|Diagnosis & troubleshooting|
|Choke Operation and Adjustment|
|Float Level Adjustment|