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New here and new to 4-wheeling. My buddy gave me a 2001 scrambler 500 2x4. He said it sat all offseason, but when i picked it up it fired right up. I ran it in my woods for a few days and then I started smelling gas realllly bad. The gas was leaking out of the vertical metal tube that is cast into the bottom of the float bowl. I thought the horizontal allen head screw was a drain so i tightened it up. still leaked, so i tightened more. Bad move ill explain later and it still leaked. Also at this time with this screw all the way in the bike would not idle at all. So i tore into the bike and took out the carb. looks as if i tightened the screw in to much and put a small crack in the bowl. Got a new one in the mail as we speak. Also it apears that this is not a drain but some sort of jet adjustment or something. there is a brass cylinder 1.5" or so long, 3/32" dia. that shares this passage in the bowl and has a small pin hole at the top in the side. jet?? I am guessing the screw has to be closed down or no fuel will flow through. Also when taking the fuel tank off i find a 1/8" tube that comes from an elbow up by the fuel fill. it looks like this was to slip onto the metal tube on the bottom of the flow bowl to prevent the leak???

questions:

1. what is the allen screw for and does it need to be open? and if it is to be open mine seams loose enough to just back in or out when the bike is running. single slugs are not the smoothest of engines. lol.
2. does that 1/8" poly tube slip onto the metal tube on the bottom of the bowl?
3. is the brass cylinder a jet, overflow, what??
4. I sprayed the snot out of the carb with cleaner and blew it out with a compressor. I really do not want to take out any jets or anything but would it be a good idea? It idled and ran great before this.


thanks for any and all help.
 

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cant find a photo

I will post pix after work. but this is the most similar i can find right now.

the brass rod i am not sure what it is. and should fuel come out of the metal cast in tube.

thanks
 

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pix of the carb

so is the brass tube shown an over flow for the bowl? if so then the screw shown should be tightened down all the way to make it fuel tight? what would cause my float bowl to stay filled up? the metal tube at the bottom should not be attached to the poly tube from my tank?

I also have a rebuild kit on the way. youtube'd a rebuild and it does not look hard at all.

thanks for the help guys!
 

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Floats may need setting or the needle / seat may be worn, allowing the bowl to fill too high. This can also affect the way it runs. The vent on top of the tank should be run down and tied to the frame to vent the tank and create an air lock if it goes on its side or underwater
 

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Tube on bottom of float bowl

The tube coming off the top off the tank is a vent tube. The tube inside the float bowl should not vent to the outside
Spitfire: Are you saying the tube coming off the bottom of the float bowl should not vent? Mine does unless it came off somewhere. It is also leaking like a fire hose! I thought that I had a stuck float or needle valve. Being a novice at this, I thought that I would ask your opinion. Thanks.
 

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You need to get a repair manual asap. The tube is overflow and your float needle valve is leaking if you're leaking fuel out the overflow. I can't tell from the pics but you probably were turning the air screw in which would explain why it wouldn't idle after you adjusted...it should be about 1.5 to 1.75 out from seated to be right.
 

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Nathaniel, before I bought my Polaris a month ago, I had a Chinese 400 4x4 ATV with the same issue. I'm just now getting into trying to repair minor stuff like this myself. On my Chinese ATV (before I sold it), I let it sit for a while (month or so) without starting it. One day I noticed the smell of gas in my garage. I didn't think much about it, because I had just bought a 14ft Jon boat to duck hunt in and had torn everything out of it to sand it and camo it. That included the gas tank, so I thought that was the smell. Long story short, next time I went to start my 4 wheeler, it wouldn't start. I tried and tried and finally found it was out of gas, and that was the smell from the weeks before. I knew that couldn't be right because I filled it up before last ride. I filled it up again and gas started coming out of a tube like you are talking about. Father in law works on these and told me to put an air hose up to it and blow because the float was probably stuck in the carb from not running for so long. The gas we have now days (at least in Texas) is the worst for these. He said that he would also run a little fuel stabilizer in every tank if I wasn't going to start it at least once a week. He rebuilt that carb for me and everything was fine. He said it was black on the inside from the old gas sitting in there and that was only from sitting for a month or so. Also, I think the screw you are talking about is an "idle screw" you can start your ATV and loosen it and tighten it and it will either idle higher or lower, but i'm not sure.
 

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when you open the screw its to remove stale fuel,the bowl is designed to overflow out the cast tube with a rubber tube attached out away from the engine instead of flooding the motor oil.i have another bowl if you need one.
 

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Leaking fuel from carb bowl Polaris 500 HO

I gave up and brought it to the dealer in Hill City, MN. 40 minutes later I had the machine back, problem fixed (sticky needle valve and bowl black with crud.) Cleaned it up, changed the oil/filter, air filter, differential,grease, plug. $160. SEE YA! I like working on machines but sometimes my time is more valuable. One thing I did learn from the mechanic is that even if you tighten that screw for the drain down tight it will still drain out the tube if there is too much gas in the carb bowl. He was right. I still might get a service manual just because I know I can't help myself by trying to fix things!
 
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