Alright i jumped up to the 50NL (thanks scrub)

[Ulysses]

My thinking was I was trying to represent an Ace with Med. kicker trying to run him off.

Exactly why you need to bet again, right? Because if he thinks you have something like A9, he'll check behind w/ something like A7. He might even check behind w/ something like AJ. But he very well might call a bet w/ those hands since he seems pretty wiling to call so far. And in general, guys that just call are less likely to bet than guys who raise - another reason to bet.