Tach hookup on BF50

[Craniac22t]

I recently got a '99 Honda 50hp with remote, and TandT for my Whaler. I have the wiring harness for the dash, and wonder if I can hook a Yamaha digital tach and trim gauge up to it. I've been fiddling with the wiring, and the tach will come on to zero, but the trim gauge doesn't stabilize at one point. I haven't started the motor yet because I don't know if I can damage the engine wiring if I have something wired to ground or something. The tach is off a 2 stroke Yamaha, but has an adjustment pot on the back. Think there's any chance that it'll work and read the right RPM?
I have the Honda manual, but the yamaha wiring is not to the same color code as standard. I did manage to find the yamaha wiring color code online.
Thanks for any help you can give me.

[boats.net]

If the Yama tach is 2001 or newer then will work, set tach settings for 6 pole alernator and 2 wire trim sender.
Tach Settings.JPG
Honda black wire is ground , connect to black Yamaha wire
Honda Black/Yellow is key on power, connect to Yamaha Yellow wire
Honda Gray is tach signal, connect to Yamaha Green wire
Honda Red/White wire is backlight in gauge, connect to Yamaha Blue wire
Honda Yellow/Blue wire is trim sender, connect to Yamaha Pink wire