HELP - tach hookup on a late Merc 40m

[cory]

River racers, need some help. Trying to hook up a standard Teleflex tachometer to a 2005 Merc 40 manual. Got the electric reg/rec and have the two yellows hooked up to the stator. Grey hooks to the tach. Tach set on "6P" for 12 poles. Question is about the two reds; one to the battery for charging and the other red (sensing)? Do I hook these together to the battery?? Thanks.

Cory

[Fast Fred]

not sure on what you said, three wires, a pos +( goin to the pos on the bat)
a neg(should be black, to the neg on the bat) and the sender goes to the alt.
thats all ya need to run the tac

[cory]

Hey Fred, thanks for the help.

New style reg has 6 wires. Rectifier inside. 2 yellow (to stator), 2 red, 1 grey (to tach, like the V6s), and one black (to ground). The two reds are where I'm confused. Service manual lists one as the sensing and one as charging. Evidently, the regulator senses required voltage from battery and applies accordingly. However, I don't know if these wires are simply hooked together at the battery or do I need to wire in a diode to seperate? I just want to make sure I don't fry this $140 dollar part!

Thanks. Keep them superfast Yammies comming.

[Fast Fred]

was thinkin it sounds like a main bat. switch set up, so, if you shutoff the bat. switch off when it's runnin ( not sure why you would) thare is a dioad loop so not to fry the alt. thinkin it sound kinda like that for what you said.
same sorta kinda set up on trim switchs ( left , right, and a Main).
got more info?:cool:

[cory]

Fixed it....forgot I had to share grounds between the tach and the reg. THANKS CAJUN OUTBOARDS!