tach wire

[splitshot]

trying to hook up a teleflex tach in a boat my father in law just got everything is hooked up except the wire that goes to the coil it says hook it to the negitive side of the coil...the motor has 2 coils and each one has 2 orange wires comming out..one goes to the mounting bolt which holds the coil on and the other one goes to a black distruibution box and then out of the bottom of the coil is the plug wire and hooks to the spark plug...where do i hook the tach wire ?? i tried the one that goes to the mounting bolt nothing...so then i tried the other orange wire (goes to the junction box) and i got very few rpms on the guage itself while the motor was idling perfectly the guage read about 400-500 rpms....???? the guage looks brand new but i dont know how old it is but looks right out of the package...thanks

 

[Silvertip]

Re: tach wire

It would really help if we knew what you were working on!

 

[splitshot]

Re: tach wire

ok ok i may have left that part out :redface: 1987 50 hp 2 stroke johnson no vro..

 

[Silvertip]

Re: tach wire

The reason you are having trouble is that you do not connect a tach to the ignition coil on a two stroke motor. The tach counts stator pulses so it gets connected to one leg of the rectifier. You have the wrong instructions, or you have a tach with instructions that are telling you how to install it on a four-stroke motor (I/O for example which is essentially a car engine). If the back of the tach does not have a dial that allows you to select the number of pulses, you probably have the wrong tach. That setting should be 6P.

 

[splitshot]

Re: tach wire

i have the selector on 6p what does the rectifier look like...is it the black box the 2 orange wires come ouit of for the coils ?? i think it has a few more in it too....if so how do i know which wire to connect to thanks for helping me i appreciate it...the instructions were from the teleflex website

 

[Silvertip]

Re: tach wire

Check your control box right below the key. There may be a three terminal receptacle there. If there is, that's the power, ground, and sense line for the tach. There is a gray wire going to that connector which is the tach "sense" connection. If there is no connector, check for a gray wire in the wire harness going to the control box. If there is no gray wire, then at the engine, connect to either the yellow wire or yellow wire with a gray tracer. The rectifier (or rectifier/regulator) is fed by the stator under the flywheel. Your engine may have a combination rectifier/regulator but it will still have the same two wires.