AEM Infinity 308 Start Up

I have a AEM infinity in my marine application but for all intensive purposes its a 454 big block with a roots 250 blower on it with cable driven throttle bodies. On start up I found that I need get it about 15% ish throttle to get it to pop off and fire. Now this is not a huge deal and easy to do in the boat but figured I might be able to tune around this. My first thought with this was just it being a air flow issue and thought I could use IAC valve just have it wide open during cranking then move back to normal once started but open to ideas.

Thanks,

Nick