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ok so,

I checked everything you mentioned. I tried both carbs on the ATV today, the new and old one and they both overflow. Also took apart each carb and checked everything...it is cleaned as can be. Floats are well adjusted (that I know of), when I raise the floats gently by hand while I blow in the fuel line, it shuts off.

How much play should the needle have to seal with the seat? 1/4 in or?
 

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Is there the remotest possibility you have the fuel line and vacuum line inverted or have the fuel supply line on a float bowl vent nipple?
 

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Pull the pulse line off and crank to see if you have fuel coming through it... to check if the pump diaphragm is leaking.
 

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Because the if you are talking about that line, it's got fuel coming out of it all the time, especially when I crank.
 

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It's got a constant drip coming out of it. Does that mean the fuel pump diaphragm is bad and allowing the carb to be flooded?
 

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Well, if has fuel coming out of it and it's the vacuum line, then it is supplying fuel directly to the intake and bypassing the fuel bowl on the carb - there should be no fuel coming out of that line at any time.
 

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Ok. Can you confirm which line is the vacuum line and which one is the fuel supply?

I looked up a fuel system diagram and the bottom black hose should be the fuel line right?
 

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Based on the specs the quad has a VM34SS Mikuni carb - we experienced mechanics may have been providing you with inaccurate information - it is the difference in working on them and describing them.

The VM34 carb fuel system does not have a vacuum port - it instead only has a fuel line from the fuel valve to the carb.

Fuel flows from the outlets on the fuel tank to the petcock and from the petcock to the carb
Fuel tank below - carb farther down
137920

The carb has only 3 nipples identified in the following pic
137921


With the fuel line connected to the proper inlet nipple and the float needle seat screwed into the carb body, the only reason for the carb to over flow is:
floats not floating
float level incorrect
float needle not shutting fuel off
defective float bowl (damaged by water/alcohol)
and if the float bowl has an overflow pipe - the pipe may be cracked or split (I don't believe the VM carb has the pipe)
 

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Uh Uh… a 2004 ATP 500 4x4 has a pump and therefore has a pulse line on the carb.
Bear, the pulse line nipple out of the pump is marked with a "P" like the picture in the first link below. It should NOT have any fuel coming out. It attaches to the nipple on the LEFT front of the carb closest to the engine and beside the choke plunger #11 and 13 in the second pic.
The fuel supply line should have a full stream of fuel anytime the tank is completely full or during cranking. It attaches to the elbow nipple on the RIGHT side toward the REAR of the carb just above the bowl. Its beside where the throttle cable and idle screw cable are located.
137925
 

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What we have here latebird, is the OP's thread with the 98 Explorer has been hijacked by BEARGLOVE with a 2004 ATP 500. I'm answering one and you the other lol.
You need to start your own thread BEARGLOVE. This gets confusing for everyone... or maybe just me? lol
Sorry OP
 

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Ok, I looked back to the beginning and see what happened now. BEARGLOVE revived a 7 year old thread about a totally different machine rather than start a new thread to ask a question about his machine. You need to start a new thread in the appropriate forum section BG when you have a question. Tagging your question onto a years old thread about a different machine causes mix ups and erroneous info to be given.
 

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Hey, no problem BG. It takes a little while to get used to the forum ins and outs. latebird is just about always spot on so when he posted that about the older style carb I new something was amiss. That's when I started looking back at the original posts.
Check that pulse line to make sure you have things correctly connected and we'll go from there to get your carb problem fixed. It might help to print out my post #34 with the diagram to take to the garage with you.
Good luck and let us know what you find. (y)
 
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