See full version: Do I Need To Adjust My Float Height
Float level is too high
If the float height is too high, this will cause the fuel to rise to a level above the operational spec. If the fuel height is a bit too high and the bike is running, the engine will display a rich running condition, which will make the throttle response slow and the engine note muffled. This condition is usually accompanied by a strong smell of unburnt fuel from the exhaust.
Another dangerous issue caused by fuel leaking from a carb- fire! And no one wants to ride a bike roasting their crotch on an open fire!
Float level is too low
When tuning your carb or carbs, it is important to be detail oriented and pay attention to whats going on. If the float tabs get bent or moved out of place, this can drastically affect how your bike functions and for such a simple part, can cause a LOT of issues! more
What the hell is a float and how does it work?
The float does what its name implies, it floats at the top of the fuel in your float bowl, and is attached to a needle that is situated in the float valve. The float needle is rubber tipped and when the float rises the needle is pressed into a V-shaped seat which then stops fuel from coming into the bowl. As the motor-generated vacuum draws fuel up and out of the carb via jets and fuel and air passages, the fuel level in the bowl will drop, thus releasing the float needle from its seat and allowing more fuel to flow into the float bowl. more
If the holley float level is too high there will be flooding or fuel spilling over into the venturi of the carburetor unmetered. more
In order for proper fuel deliver there must be a proper fuel level in the carburetor fuel bowl. Whether it is a 1, 2 or 4bbl carburetor.
If the holley float level is too low there will be a lag in take off or lack of power as the RPM increases. Sometimes there will be surging at cruising speeds.
If the holley float level is too high, put the sight screw back in the fuel bowl and loosen the screw on the top of the fuel bowl and turn the nut below it clockwise 1/2 turn and tighten the screw back down. Start the motor and run for 30 seconds. Turn the motor off and wait for 30 seconds. Then remove the sight screw again to see if fuel trickles out of the hole. If not, then repeat step until it does. Each time remember to put the sight screw back in to the fuel bowl to avoid fuel spillage.
Problem: Engine is running lean. more
For some guys, it’s a symbol of American automotive performance…a genuine hot rodder’s answer to the “evils” of modern fuel injection. For others, it’s a source of great intimidation and frustration.
Solution #4: If you have a carburetor with an electric choke, check and adjust the choke flap to make sure it is opening completely. If it is not opening all the way, there will be an airflow restriction that may cause your engine to run rich.
Solution #3: Airflow restriction can also cause an engine to idle poorly. If you have a carburetor with an electric choke, make sure the choke flap is opening properly and adjust if necessary.
Step 2: Check The Fuel Pressure
Attach a fuel pressure gauge and check the fuel pressure. Flooding will happen when pressure exceeds 7.5 psi. According to Holley fuel techs, the fuel pressure should be no more than 7 psi; 6 psi is ideal.
Step 4: Fuel Level Is Too Low:
If you didn't see any fuel trickle out of the sight plug, the float is not allowing enough fuel to get into the fuel bowl. more
f) Turn the adjusting nut counter clockwise while holding the lock screw in place up top. This will let the fuel levels rise in the bowl. Keep turning until the fuel level reaches the bottom of the sight hole and starts to trickle out. [links]
First, it's important to know how the fuel float system operates. The floats, located in the fuel bowls of Holley four-barrel carburetors, control the fuel delivery system and ensure that the carburetor has a sufficient fuel supply. Some of the most common symptoms of improperly adjusted or sticky floats are hesitation on acceleration, a rough idle, flooding and misfires. Obviously, making precise fuel float and in turn, fuel level adjustments is difficult on a misfiring or rough idling engine. So the procedure to adjust this has to begin without the engine running.