Ok guys I need some help....My 300 4x4 cat has been sitting for a while. I went to start her up and she will not stay running. It will start up and run only if I have the throttle open. Then it starts puking fuel/oil out of what (looks like a 3/4in. tube) on the left side by my foot. I followed the tube and goes from the left foot area, up under the fuel tank and to the rear of the engine. Thinking it was the carb. I rebuilt it. Same thing is happening.....Whats up?

 

If its gas, coming out the tube, i would think you have a stuck float,or dirt between the needle and seat . The fuel is coming out the overflow tube. That would definetly cause your poor running problems.

 

It is gas. It looks to be mixed with some oil also. I have replaced the needle valve and seat and the float still floats. So I have no idea. The thing that throws me is this tube is not on the carb. it is coming from the rear of the engine.....Im no ATV Mechanic (Obviously) so I'm lost. The next thing is to buy a new carb. [img]i/expressions/face-icon-small-disgusted.gif[/img] I have had the carb torn down so many times the screw heads are starting to strip out.[img]i/expressions/face-icon-small-confused.gif[/img]

 

When you said it was 3/4 dia I thought it wasnt an overflo tube, is it a vent tube for the crankcase? Have you checked your oil? Does it smell of gas too? You probably dont need a new carb, try to fix the one you got. Do you have a service manual for it? do you have mechanical abilities?Got a riding buddy thats good with motors?
is it the hose #12 in the picture, here?a c parts Does it go to the air box? Can your cats gas be turned to off?Or do you have a vacumn operated petcock?
Go to this websiteac parts finder and see if you can look thru the drawings and identify the hose, or where it comes out.
Maybe someone who has another 300 ac can help.

 

Your needle probably stuck from varnished fuel. This allowed fuel past carb and into crankcase, if oil is contaminated with fuel DO NOT RUN, oil is thinned down and not providing good lubrication. Replace needle and seat, clean carb, change oil and filter. You should be alright, start using fuel stabilizer year ruond if you aren't already.