Hour meter insall on Yamaha two stroke

[Bonefishr]

I run a lodge in the Bahamas. I have four new 60hp Yamaha two strokes I'd like to install hours meters on. These are pull start motors....there is NO Battery. The meters have two leads, neg and pos. The negative is easy enough. For the positive....One mechanic said to tap into any yellow wire. Wrong....the only yellow is temp alarm and only goes hot when overheating. I read to splice into the run/kill switch.....nope, doesn't work. I read to hook it up to the tach. Nope....the voltage is varible and will burn the meter up. Another Yamaha mechanic said I would need to install a rectifier. Won't I need a voltage regulator also? You get the idea....Can someone please give me a straight answer. Thanks in advance.

[rodbolt17]

without spending a bunch on batteries and rectifiers your hour meters simply wont work.
google mechanical hour meters and inductive hour meters.

[Hipster]

Tiny-Tach works great.
Spark plug wire only.