A couple of months ago I was running about 3/4 throttle and the quad shut off, I noticed gas running out of the overflow. After a while it stopped shutting off but still leaks gas out of the overflow, while riding and just sitting. I have asked profestionals but they do not know. Does anyone have an idea what is wrong?

 

Sounds to me like the main jet is to big and the excessive gas is flooding out the carb.

Go to a smaller main jet, the smaller the number the smaller the jet. But start by going only one size down, so for example if it's a 230 go to a 220.

GOOD LUCK!!!

2000 SCRAMBLER 400 2X4

SCRAMDADDY400

 

Sounds to me like your floats are sticking

I could be wrong but check it out hope this helps

 

Your floats slide up and down on 2 rods. If varnish builds up on the rods your floats can't slide freely and your needle could stick in the open position. Just something to check.

 

Pull the carb off, remove the float bowl and check that the floats move freely, and remove the float needle and check that there's no trash in the seat. Also, check the viton tip ( black or grey portion ) of the needle to see if it's deformed or damaged. Replace the needle if it's damaged. If there's trash in the seat or in the float bowl, clean it out and replace the inline fuel filter.
If you're using steel fuel cans, there may be some rust in them being transferred into your quad.
An old trick is to use a paint strainer or coffee filter in a funnel while you fuel the tank to catch any garbage.

 

That is exactly what happened to me on my Xpedition 425. All of a sudden it just quit, and I smelled raw gass. I sam it leaking out of the carb drain tube. I shut the gas off, and opened the drain. There was a LOT of gas in there. I cranked it over whenI turned the gas back on and it ran fine. I would just try flushing the carb, which is essentially what I did.

Good Luck
Mark