Funk is very riff bases and there are certain types of rhythms you need to stick to to make it really funky but it can work in other ways, scales are important, standard chords not so much but if you learn some unusual ones it can help, also practice funk songs and making your own to really get funk improv. down.
Unfortunately i'm not good with scales, I only know the basic ones so i'd start there, for songs try some Chili Peppers or Rage Against The Machine/Audioslave, Tom Morello and John Frusciante are good funk writers and John is a great funk improviser, especially at live shows so they may be worth a look up on Youtube.
i dont know it very well in terms of theory, but from what i jam to and hear, most funk scales are based on combinations of the dorian, blues, and sometimes mixolydian. Mostly dorian, but i say "based on combinations" because you wouldn't go straight up and down these scales, but find melodies and rhythms within while improvising. It's very jam-based, and hard to explain, but as aaciseric said, john frusciante is a great funk improviser and watching the way he "messes around" while soloing will give you a basis to build from.

Usually the variations with the dorian scale are because funk sometimes uses "off" notes. I'm pretty sure they all follow modes and what not, but knowing as much theory as i know, i would suggest learning dorian as its used most in both solos and rhythm/riffs
oh and songs; maggot brain. If you could not only learn the song, but study the music and theory behind it, you would know funk guitar.
When it comes to funk, scales aren't AS necessary as they are with other genres.

But you still NEED to know them to be able to improvise.

Alot of funk is based on major scales and pentatonic scales.

For example, a lot of the album BSSM by the chili peppers was written in A minor pentatonic.
people seem to be repeatedly saying that RHCP is funk, they are good, they are funk influenced, but not at all funk, check out bootsy collins and parliament, try some james brown too.

that said, NWA had as much funk influence as RHCP lol check that out

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yes parliament.

and funk is a feeling --> rhythm and phrasing. there is NO funk scale.
Parliament, Funkadelic, Sly & The Family Stone, James Brown...

Go and listen to some funk. Then learn some funk songs. Then analyze them.

Then answer your own question.
Quote by Johnljones7443
my neew year reslosutions are not too drikn as much lol.

happy new yeeae guyas.