Allright fella's, I've got a stupid question! I am screwing around with a carb on a 01 sportsman 500, I had to replace the needle valve because it was flooding gas into the motor. (oil was diluted with gas)
Anyways, my question is simple, what exactly does that screw/valve do on the bottom of the bowl? It has a small hose attached to is with a small plastic checkvalve. Im used to snowmobile carbs and they don't have this little doodad. I thought is was just to drain the bowl, so I tightened it up all the way, but now I noticed there is more to it....the copper tube inside the bowl makes me think it is a vent.

The 4-wheeler is starving now since I put it back together, so I am thinking I need to open that screw up a bit?? Please advise!

Thanks!

 

that screw is indeed the carb bowl drain screw, keep it tight. the brass tube you speak of is the overflow tube which will allow fuel to drain out of the bottom of carb if the level gets too high. sometimes you may get a few drops just from normal splashing around of fuel in bowl. if you are now starved for fuel perhaps the float is stuck and won't allow the needle valve to open. did you put that little tab on the float through the thin wire keeper on the needle valve? when the float moves up and down it opens and closes the needle valve by way of that wire keeper area. if all is assembled properly then spray it all with carb cleaner and make sure the float moves freely, it should move with the slightest touch, spray the hinge pin generously. if that doesn't do it then you may need to adjust the float, has it been messed with? maybe someone tried to adjust it for less fuel when it needed a needle valve and now with the new one it is starved? let me know.

 

Thanks for the detailed reply Zerowick!
To answer your question, yes I did put the tab on the float through the wire on the needle valve. I cleaned everything real good with carb cleaner, and everything appeared to be working properly. However, it still seems to be bogging. I tried opening the choke when it starts to bog, but it doesn't help at all, so it doesn't appear to be any type of a lean bog. I don't think that anyone else has ever messed with the carb, but its really hard for me to say.
I noticed, when I put the float back in, the rubber O-ring on the base of the white float assembly, where it fits into the carb, seemed like it might have been stretched a little bit. I wasn't sure how good of a fit I was getting, but it appeared to be sitting properly. I guess I might have to take it apart again and check it over. I didn't screw around with any adjustments, so Im not sure why it is acting up. When he brought it over he never mentioned anything about it running poorly. All I was supposed to do was change the oil, and then I found that there was more gas than oil in the oil, so that led to this carb work. I must have done something along the way that is leading to this starving/bogging.

 

you can check the float/fuel level in the carb with the clear plastic overflow tube that hangs from the drain nipple on bottom of carb bowl. take check valve off plastic tube if there is one and reconnect long section and run it along side of carb. start machine and let it idle for a minute to establish consistant fuel level. shut it down and with tube along side carb the fuel level should be very close to the mating surface of bowl and carb body. for my machine the level should be within 1.5 mm or .060" of mating surface. not sure what it would be for your machine. if you want a pic of this method send your email in a PM.

 

Zerowick,

Thanks so much! I checked it out tonight and the gas level was almost a quarter inch above the mating surface. I adjusted the float and now it runs perfect [img]i/expressions/face-icon-small-smile.gif[/img]
You learn something everyday!

-Steve

 

cool beans! glad I could help!