Confirmation on tach setting

[JerEazy]

1975 50hp 50573b

installed a tach and set the dial in the back for 6 p - but now I’m curious - I saw some conflicting info only that the 50 should be set at 5p?

but this info also said for 77 and later - so I’m not sure if my 6 setting is correct or if I should set it to 5?

thank you in advance.

 

[F_R]

My knee-jerk answer would have been 5 pulses, but it appears that is incorrect. Should be 6. Look at your rectifier. I think you will find it has two yellow wires (6 pulse system). 5 pulse systems have three yellow wires.

 

[JerEazy]

My knee-jerk answer would have been 5 pulses, but it appears that is incorrect. Should be 6. Look at your rectifier. I think you will find it has two yellow wires (6 pulse system). 5 pulse systems have three yellow wires.

You are correct - 2 yellows and 1 red. Recently replaced it - so that I’m sure of.

6 it is! Thank you