bought a repoed 600DVX it was running realy rough so i pulled the carb and tor it down finding blocked fuel screen, green crap in every thing. cleaned every thing jets and alike also cleaned out gas tank and supply valve.

Now i can'r get it to start. it will catch a little if i put my hand over the intake of the carb but then it dies right out... any suggestion??  

sounds like when you cleaned you left a little in and it got loose and is plugging it up again. yank it out again and clean also check the choke to make sure it is unobstructed.
give another good cleaning you should be right now.

inspect the rubber intake boots for leaks too.

pull the jets off and make sure yu can see through them good.
if not take a wire bread tie andburn the plastic coating off, and push it through them.
if you have a .10 or .11 guitar string that will work as well.