This weekend when riding my atv worked awesome for one day. Second day I was riding and after about 6 miles when I went I let off the gas my atv quit and backfired. When I went to go start it, it would not start. After letting it sit for about 15 min it fired right up. It ran great for about 3 min till I let off the gas then same thing. It will run or start up and run fine for about 3 min then start to run ruff and dye like it is not getting fuel. I have replaced the plugs and put in fresh gas. I think it is the fuel pump, however have you quys experienced this before. I think the vacuum fuel pump is not making enough vacuum. Please help me out on this one.
Thanks much

 

Mine acted similar, tried a new pump, plugs ect, no help, finally saw a worn spot in the breather line from the engine to the air box, removed the whole line, plugged one end and blew through it, it had a pin hole in the rubber hose, replaced that piece of hose and it runs fine again, hard to believe but true, check your vent tub from motor to airbox.

 

Had this same thing happening on my 04 700. There was a crack in the rubber manifold (connecting the carb to the head) It ran along the bottom of the manifold and was almost impossible to see. When the engine would get warm it would expand and the crack would open, sucking air, cutting out, and would die. When cold ran fine.

Trooper

 

Thanks much guys for your replys. I will have to take a look at it tomarrow when I get time. This sounds just like what you are saying. It starts up fine but after warm runs like crap and quits.
Thanks

 

trooperK you have to me kidding me. Sure crap I went out and took a look and on first side nothing on the bottom side sure enought it was cracked. Thanks so much for the help guys. Saved me some time and money.