Yup. Check that the bowls have fuel. Don't use the starter fluid. Period. EVER! (Unless you KNOW your engine is perfect and you are in sub-zero weather!) It absolutely positively is only useful as a finder of vacuum leaks.
Did it run before you cleaned the carbs? Did you replace any of the brass when you rebuilt them? If so, and you did not buy authentic OEM parts, put all the old brass back in. I have "repaired" more "freshly cleaned and rebuilt by the dealer (etc)" carbs than I can count simply by throwing out the aftermarket rebuild kit brass jets /needles and replacing them with used OEM parts (and actually properly cleaning. If you think all you have to do is throw the carb bodies in an ultrasonic cleaner, think again). If it ran before you worked on the carbs, the problem will either be in the carbs or in something you worked on in order to get to the carbs. I've also spent more than a few minutes chasing a problem I created by incorrect assembly/forgotten part, hose, connection etc when absolutely sure it was right, so re-checking your work is never a bad idea.