The funk solo sound isn't in the scale you use, what's distinctive about funk soloing isn't in the harmony implied. Jon had the right idea, it's basically pentatonic. If you'll look you'll notice that those chords resemble very very closely an E 12 bar blues. The way to make a solo sound like a funk solo instead of a blues solo is in the feel. Play rythmically, try including a lot of octave jumps, those are common in funk riffs. Maybe try playing muted notes, and try including chords in your solo. These are just ideas, but what it comes down to is that you have to make it sound like funk, and no one scale will do that for you. (You could also try arpeggiating the chords to be more interesting. I'm not sure if its a funk sound, more of a jazz thing, but it will make your solo more harmonically interesting.)