Where to attach Tacho?

Grant123

Cadet
Joined
Jul 28, 2007
Messages
23
I have a 1982 2cyl 60Hp Mariner 2 stroke outboard. I would like to temporarily attach a tacho gauge whist tuning the fuel mixture. Where do I attach the two clips? Also, my hand held tacho gauge has a scale for 4cyl and 6cyl but not one for 2 cyl. Do I halve or double the 4cyl scale perhaps?

Thanks Grant
 

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: Where to attach Tacho?

It sounds like you have a auto tach, if so don't try to hook it up or you may burn it or the ign up,
 

Silvertip

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Sep 22, 2003
Messages
28,758
Re: Where to attach Tacho?

Tachometers are generally capacitor coupled so there is little danger of destroying either the ignition or the tachometer. The question is whether or not the tachometer can recognize the pulses it is seeing. As for the setting, a 2 stroke engine fires each cylinder every revolution of the engine whereas a four stroke fires each cylinder every other revolution. Since your tach will be connected to the primary terminal on a coil for just one cyliinder (each has its own coil) the tach will see one pulse per rev whereas on a four cylinder auto engine it would see two since there is only one coil). Therefore, on the 4 cylinder setting, you would need to double the reading.
 

Grant123

Cadet
Joined
Jul 28, 2007
Messages
23
Re: Where to attach Tacho?

Thanks Silvertip, Regarding where to connect, would that be to the ingition lead which goes to the spark plug or the wire which leads into the coil which come from the junction box I think?
 

Silvertip

Supreme Mariner
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Sep 22, 2003
Messages
28,758
Re: Where to attach Tacho?

Definitely NOT the ignition lead unless the tach has an inductive pickup intended for that purpose. The primary connection on the coil is where you attach the tach.
 
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