How do i hook up an external tach

[jerryny]

I have a Johnson 88hp SPL engine. I want to hook up my automotive tach to watch the RPM's. Does anyone know where I would connect the clips. thanks in advanced.

 

[bplayer405]

Re: How do i hook up an external tach

It kind of depends where you get your signal from the outboard. If you have seperate coils per cylinder on your engine then you could find the ground feed (not ground but an alternating ground wire) on one coil to hook up your tach. But remember that an automotive tach is strictly 4-stroke and you'll have to set the tach on 2 cylinder for it to read correctly. This worked with an old SunPro tach I had, but I ended up getting a cheap digital hour meter tach fort lead than $20 to check mine.

 

[boobie]

Re: How do i hook up an external tach

Check out Tiny-Tach.com.

 

[glenn property of pam]

Re: How do i hook up an external tach

last small digital tach/hour meter i used you only had to ground the black and wrap the red around a plug lead, set to 2 stoke and it was done

 

[jerryny]

Re: How do i hook up an external tach

The boat has a tach, its just not working. Where would Chappall hook up the tach to the Johnson 88HP SPL engine. Anyone have any ideas. Thanks in advance.

 

[Chris1956]

Re: How do i hook up an external tach

An automotive tachometer may not work very well if at all. OB tachometers use stator pulses to detemine RPM. You can try connecting the non-ground side of the tach to the grey wire at the stator or near the voltage regulator or rectifier, and see what you read. The alternative would be to attach the tach to one of the coils primary winding and mutiply the reading by 4.