A couple of silly questions.

[Oceannavagator]

I'm trying to straighten out the dash wiring on a boat that was initially wired by bears. The same color wire was used on the entire dash leading to some confusing moments.
After unwrapping at least a roll of tape from the harness I've exposed the engine harness and have 4 wires. One black (ground) one yellow (ign) one green (tach sending) and one capped off red wire.
My wiring diagram in my yamaha manual reads like chinese arithmetic when it comes to the dash panel and I wonder if anyone could tell me what the red wire is for? The engine is a 2008 F115 LTR.
Also, I was surprised at the small gauge of the ignition wire (looks 16ga or less) is this correct?
Thanks

[rodbolt17]

the red s constant 12V+ anytime the battery switch is on.
its for a speedo memory circuits.

[Oceannavagator]

Ten thousand thanks man! So now I'm assuming that the ignition wire is only for running the instruments and anything else that draws power should be directly from the battery. Correct?