First off, I'm posting this with the understanding that the 1.9.4 branch is supposed to be 1.10.2 compatible. If it is not, please discard my report and chastise as needed.

Caused by: java.lang.NoSuchFieldError: field_180413_ao
    at mekanism.common.Mekanism.onBlacklistUpdate(Mekanism.java:1501)

I'm running:

Minecraft 1.10.2
FML 12.18.0.2008
MCMultiPart-experimental-1.2.0_73-universal (I've also tried the 1.2.0-universal, same issue)
Mek 1.9.4 branch freshly built.

I re-cloned and rebuilt the 1.9.4 branch twice for good measure. I've also removed all mods except MCMultiPart/Mek and experienced the same crash. Reverting to FML 12.18.0.2007 did not resolve the issue.

Paste located here: http://pastebin.com/Z5z5Khjw

1.10 is not supported, I have not yet completed any port. For that matter, 1.9.4 isn't supported yet either ;)