ltnitemechanic

I have a 2000 sportsman 90 with fresh gas and a clean carb. This machine starts great idles perfect and will run for about 500 ft then boggs as if it is running out of fuel. but the carb bowl is full and it will still idle but will not pull or accelerate. When switched off and it sits for a while the same thing happens it runs great then boggs. could this be electrical? if so where do i start?