Tachometer Cable

Hello everyone,

I had a situation where my tachometer cable came loose at the tachometer. I
reattched it as tight as I could be hand and is holding so far. I wanted to
know if I should try and tighten it more using pliers, or could that cause
damage. Or is it common practice to apply something to the threads to
assure it holds?

There isn't much room behind there to work.

Thanks,
SAC