I had an OS F plug in their but I just changed it out with a YS Four stroke plug. The element in the OS plug looked a little white. I also run PowerMaster 20/20. I'll tweak the regulator until the midrange is right on, then readjust the top end and then readjust the low end. Does that sound like the right order? I think I'm pretty close. Hopefully that will do the trick. I also bought an APC prop and reset the valve clearances.