installing tach 4 cyl inboard

[Randy stoner]

I have a 1991 Omc Cobra with the inboard inline four cylinder chev motor. Im replacing the indash Tach with a sieria Tach. On the back it has the setting for the engine. Instructions say set to half number of alternator poles. I have 6P, 5P, 4P8C, 3P6c and 2P4C . Of course the instructions dont tell you what one nor does the old tach have that. Help

randy

 

[Buzzsaw420]

I believe the c stands for cylinder so you would be 4c.