Tach replacement question

[smoses99]

Hello,

my tach quit and I ordered a new one. The dial on the back is different and I want to be sure I wont ruin it before I install it. The old one has 1,2,3,4 and new only 2. Not sure what those mean. Can someone take a look please and let me know. I have an 87 force 125. Thank you

 

[alldodge]

Your not going to hurt the tach or motor by not having it on the correct position. Your either going to read higher or lower then what it should if its on the wrong place. Unable to say from your pic if the tach is correct for your motor, but as before your not going to cause any harm

 

[jerryjerry05]

What are the specs on the new tach?
12 pole? 20 pole?
Can't read the back, closer pics??

You need a 20 pole.

 

[VivaLaMigra]

Numbers on the back of a tach are generally pulses per revolution which on a 2-stroke CAN be same as the number of cylinders but it depends on the ignition system or the pulse source. Some tach's work off the alternator and I know on OMC's there can be 5 or 6 pulses per rev regardless of the number of cylinders; it depends on the phases wound into the stator.