Want to know what the little brass screw on the front bottem side by float bowl is for and how its to be adjusted

Is it a Nikki carb? The little brass piece is the main jet and goes in the long tube in the center of the plastic piece that holds the float and float needle. It is inserted from bottom side and seats in the top of the tube.

Hello James --- Remove the top screw off the top of the bowl and make sure the needle is about even with the jam nut or a tad lower. This is usually real close & the best place to start. From there you can adjust as needed. You want the gas level to be just at the bottom edge of the brass plugs on the sides of the bowl. This is where having those clear bowl plugs come in handy, no gas spillage or removal of plugs is needed for adjustments. Make sure your vehicle is level when adjusting the floats. I hope this helps.

Depending upon which bowl design you have on yours, you need to check the float level. There should be a brass sight plug on the right side of each bowl. To adjust, remove one plug, loosen the screw on the top of the bowl and turn the 5/8" nut that surrounds the screw. BE AWARE...when you make this adjustment, fuel will squirt from the screw you loosened, so you need to have a rag nearby to keep everything dry. Fuel will also spill from the sight plug hole 'till it's properly adjusted. Turning the nut clockwise lowers the level, ccw raises it. If you cannot stop the flooding, you will need to remove the bowl and clean it out. You can get a complete rebuild kit from Holley (you'll need the number stamped on the front of the air horn). The kit includes new needle and seat valves, power valves and all necessary gaskets. Always use a new filter to prevent new crud from ruining your work.
If you have bad or questionable ignition wires, replace them before attempting adjustment. Float adjustment is done on a level surface with the engine running.

find the offending carb or carbs by pulling float bowl over flow hoses to the side and starting motor, 1 or move hose will be pouring fuel, follow hose to offending carb, unmount all 4 carbs from motor,(unmount tank,1 bolt 2 hoses,2 wires) then (unscew hose clamps from front and back of carbs) next(reomove scew from very top font of air box,near metal cross bar behind fuel tank) then wiggle carbs to separate from rubber intakes,unhook trhottle cables pull carbs out one side(either side of bike) once off turn upside down,take 4 bowl screws out ,remove cover,take out small pin holding floats ,needle will come with it,use the right wrench and uscrew brass seat needle came out of(make sure any rubber o ring come with) reinstall seat &any orings take old needle off float install new one,put needle in hole of seat,pin float put cover back on bottom of carb,re assemble bike.I hope you've maked where everything goes,a little oilon rubber helps with reassembly .













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Leaking gas through the air filter ports can only mean excessive gas flow from the carburator. Try adjusting the flow screws on the carburator bowl. Check all gaskets, seals, etc. and happy tilling!

Replace float. If it's a metal one, it probably has a hole in it. If its the other kind, it's probably water logged, or else your carb is gummed up and the needle valve is sticking.

I assume that your Holley is a similar age as the truck. If so I have a Holley book that I can dig out and let you know for sure, but there should be a large brass screw on the side of the float bowls. Gas should just run out of that screw hole, I believe. Floats that were too high could put gas into your oil.I'd need the model number to look it up.

Carburetors have a Float Bowl on the bottom. This float bowl has a small amount of fuel, that the carburetor uses. (The float bowl's amount of fuel, is replenished from the gas tank. The fuel is gravity fed from the gas tank, through the Fuel Line)

The float bowl has a Float Needle inside. The float needle is attached to the Float. The Float resembles a thick doughnut. On one end of this doughnut, is a flat piece of metal shaped like a U on the end. Looking at this -> U shape, there are two holes at the top. There is a metal pin that goes through these holes, and the pin is attached on it's end's, by the main body of the carburetor.

The flat metal U shape, and the metal pin, works together to form a type of hinge, allowing the float to pivot on it.
Where the U shaped hinge is attached, the float needle, clips to it.

The float needle has a tapered neoprene tip, and sits in a Float Needle Seat. This seat is a barrel shaped piece of brass, and has a tapered hole at the bottom. Fuel comes up through this seat, and the float needle regulates how much fuel can come in.

As the float drops down, it draws the float needle out of the float needle seat, and fuel comes in. As the float bowl fills with fuel, the float rises, and pushes the float back up, also pushing the float needle back into the float needle seat, cutting off the flow of fuel.

There is a specified height of the float, in relation to where the float sits in the float bowl. If the float sits too high, the float bowl fills up with fuel, and overflows. This overflow goes through an Overflow Tube, on the carburetor.
(If the float sits too low, the engine starves for gas)

A LOT of times, crud builds up in the gas tank, makes it's way through the fuel line, and gets into the float bowl. It can get in-between the float needle, and the float seat, thereby flooding the carburetor out, and fuel comes out of the overflow tube.

The float bowl is also attached to the carburetor with a brass main jet nut. At the bottom of the float bowl, this will look like a brass head of a bolt. Under the brass head is a small O-ring. This can leak. First step is too insure this is tight. (Do Not Over tighten! This is part of the main jet, and is expensive! It's Brass)

Where the outer part of the float bowl itself, attaches to the carburetor, there is another O-ring.
A large one. This O-ring, like the main jet O-ring, can deteriorate over time. Additives that gasoline has in it, heat from the engine, and heat from the sun does this. Plus just age. Neoprene breaks down after time.

It could also be that the neoprene tip of the float needle has broken down.

You indicated you adjusted screws on the bottom.
These are the Main Jet, and Idle Jet -> Air Mixture screws. All they adjust is how much air goes through these jets.
The amount of fuel going through, is predetermined by specific passageways, that are drilled through the main body of the carburetor.

This only comes into play when the engine is running. With the engine off, and fuel leaking out, you have crud under the float needle, or one or more of those O-rings has deteriorated.

The pilot jet is plugged up. Remove the water trap bowl at the bottom of the petcock, (gas valve). Is there any water or trash in the bowl? Drain a cup of gas from the tank. Is there any water or trash in the cup? Dump it, clean it and re-mount it, ( not all bikes have a water trap bowl ).

Drain the carburetor. There should be a screw on the lower side of the carb float bowl. Remove the screw then replace it after the fuel drains. remove the carburetor from the engine.

Remove the float bowl and clean the entire carb with a spray carb cleaner from the auto parts store. Wear protective goggles to avoid getting spray in your eyes. Spray into all the little airways and fittings in the carb. About 3/8" from the main jet you will see a small brass screw. This is the pilot jet adjuster. Turn the adjuster 1/2 turn counter clockwise. Make a scratch on the casing around the adjuster so that the scrach lines up with the slot on the screw. From this point, carefully count the number of turns until the adjuster can be removed. Spray carb cleaner into the jet then replace the adjuster using the same number of turns such that the screw slot lines up with the scratch mark.
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Remove the idle screw and the air screw on the outside throat of the carb and spray into the screw holes as well. Be sure to put these two screws back in the same hole they came out of. IMPORTANT > do not tighten these two adjusters down. Only screw these in until they LIGHTLY seat. Now turn each adjuster one and one half turns outward. Put the rest of the carb back together, clean the air filter and install the carb. Let the float bowl fill then start the engine. This process should get you back on the road.

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remove fuel line from petcock and see if fuel runs out, if not remove petcock from tank and clean filter screen, if it does come out, check for inline fuel filter change it, if it dont have one check fuel pump if it has one, or could be diaphrams in carb split and not building vaccuum to draw gas thru