Tachometer connection

[auto]

Hi, I have 1978 mercury 70hp outboard 3 cyl, I bought a tach and wondering about tach connection on control box, specifically what are the three connections?<br /><br /> +<br /> +<br /> +

 

[bh357]

Re: Tachometer connection

Check to see if your control box has a grey wire in it. If it does, make sure that it is connected to the rectifier at the engine. If it does, then this gets connected to the Send terminal on the tach. My control box didn't have a tach sender wire, so I ran a wire directly to the rectifier. Connect to either input terminal on the rectifier (yellow wire).<br />Connect the IGN terminal on the tach to the IGN terminal on the ignition switch.<br />Connect the GND terminal to any ground.<br />Somebody else will need to comment on the setting for number of poles for your engine.

 

[Ben Konopacky]

Re: Tachometer connection

auto; there is a brown wire from the rectifier to the remote control box tach. plug. center contact which is your sig. wire to tach.,left contact, white wire is +12vdc.to tach. and the right contact is black wire -12vdc.to tach. If you don't have a male plug go out and get one its better then spliceing. good luck

 

[Barnacle_Bill]

Re: Tachometer connection

I got curious on this one. According to my Clymer<br />manual the tach lead can be brown or gray. Serial nos below 5579017, its brown. Serial nos above 5579016 its gray. No wonder I can't keep thing straight, I thought it was just age. BTW those are US serial numbers.

 

[SeaHorse]

Re: Tachometer connection

Buy the "control box to tach" harness made my Mercury. It works perfectly.

 

[auto]

Re: Tachometer connection

Thanks guys for the info.<br /><br />Ben lucky,<br />when you refer to the center contact is this center and to the left?<br /><br />when facing plug it looks like this: (+ = contact)<br />.oooo.<br />oooo+o<br />o+oooo<br />oooo+0<br />.oooo.

 

[Ben Konopacky]

Re: Tachometer connection

auto; Faceing female plug you have 3 slots ,The 2 that are parallel,left is +,right is -and the one perpendicular on the bottom is the sig.from the rectifier.<br />hope this helps.

 

[auto]

Re: Tachometer connection

Thanks ben lucky for info very helpful, I have tach connected, however instructions say to set tach for 10 pole flywheel alternator or 12 pole.<br />I am not certain which I have, any ideas?<br /><br />1978 mercury outboard 70hp 3 cylinder 700

 

[Ben Konopacky]

Re: Tachometer connection

I believe it should be set for 12 pole.