New Engine won't turn over!! Help

Just a word of caution here. Disable your ignition when you crank it over with the plugs out. You might start a fire otherwise...

Before I'd check the floats, as previously posted, maybe you have too much pressure? Check it with a gauge and make sure it's *about* 5-6 PSI. More and you might be pushing the needles off of the seats and your just going to fill the engine with fuel again.