S motor & plug ?
 

I would like to know if a 4mm plug is big enough for a 7s motor on 2s lipo & a MM ?.

Should be more than enough.

Im going to use the 7s with a new MM esc. The MM comes with the 4mm female plug or (socket). will the 4mm male plug fit on the wires from 7s motor ?.

yeah... it's only 14 gauge wire.. I think... it should be fine... but why not just use the 5.5 mm.. ? it's about the same price...

I already have the 4mm plugs :lol:. I know they come on the MM esc. But what i really need to know is will the female 4mm plug fit the wire on the 7s ?.

It should. 3.5mm plugs fit a 10XL...