Hey Jeff, thanks for posting! The only way someone would sync from Salesforce to Emma is if they're included in an Emma Group in SF, and there's nothing in the integration that would automatically add leads in SF to an Emma Group in SF.
You would need to move those leads over to Emma Groups, either by manually moving them, or by putting into place some custom development that would move those contacts for you. We've heard from a couple customers who have had great success using a customized workflow to automatically move leads added to Salesforce into an Emma Group in Salesforce, but it's not a component we'd have support available for, since it's a feature outside of the Emma for Salesforce integration.
I hope this helps! Please let me know if you have any questions!