I found the setting for this in [templatename]/js/owl-carousel/owl.carousel.js
Look for:
Autoplay.Defaults = {
autoplay: false,
autoplayTimeout:5000,
autoplayHoverPause: false,
autoplaySpeed: false
};
Change autoplayTimeout to 8000 or whatever you prefer. Not sure why this was made so complicated by JA support. We are already working on customization, so why not let us also determine the actual speed of the slideshow? SMH