Mercury tachometer Pole setting

[Confuzed]

Hi, Just new to the forums want to say thanks in advance for help which is received, I just bought a Mercury 40hp four stroke SN OT348939 I am setting up a tach which is also Mercury, it has either "5" or "6" pole setting on the back, which do I set it to?
Thanks again

 

[Confuzed]

Re: Mercury tachometer Pole setting

Update
I removed the tach from my boat it has a label on it that has the number 176307 " for use on 5 - 6 PUL/REV Altenator equipped outboards" The dial only has a 5 and 6 on it, I am running a 2001 Mercury 40hp 4 stroke outboard
responses are appreciated
thanks

 

[Silvertip]

Re: Mercury tachometer Pole setting

Set it to #6.