Tach Issue (1985 Evinrude 70HP)

[rannrupnorth]

I bought this motor with the controls, wiring, and cables. No problem there.... Now I want to connect a Tach, but I am not sure where I can pick up the wire for it on the motor. Can anyone help? While your at it, can you tell me where the temp sensor is located? I may as well hook that up to the dash as well....
Thanks

 

[ezeke]

Re: Tach Issue (1985 Evinrude 70HP)

edit

 

[Lakester]

Re: Tach Issue (1985 Evinrude 70HP)

hello running north,

that is how my 1971 85HP evinrude oe wire diagram shows it, too. called the Tach Lead. the gray wire is 18 gauge and it comes off terminal block at terminal screw #4. may be dif for urs. there is also a black tach grnd, and it comes off the grd to powerhead connection. and it is 18 ga., also. just commenting on the gray wire, mostly. and also reviewing things on my end, too. i plan to add a tach.

regards,
lakester

 

[HighTrim]

Re: Tach Issue (1985 Evinrude 70HP)

Visual may help.

 

[Lakester]

Re: Tach Issue (1985 Evinrude 70HP)

hello ht~

thx for posting the diagram. i note in my oe service manual, it says... under electricla Do's n Don'ts...

" do not connect any tachometer, unless it is a type approved for this system.

(1971 85HP hydro-elec evinrude with points, batt cdi... running aftermarket amplifier)

in sourcing a potential tach how do i know if it is compatible with my engine's electronics? or is NOT compatible with such a system?

regards,

lakester

 

[jtexas]

Re: Tach Issue (1985 Evinrude 70HP)

upnorth, if you got the standard control box, it has a 3-prong outlet on the end of the box directly under the keyswitch - might be covered by a rubber boot - a plug & play tach wiring harness is available (got mine at BPS). if you can't find the harness or don't have the plug, run a wire (usually purple) from the keyswitch "A" terminal to the tach IGN pin, keyswitch "M" (black wire) to GND, and there should be a gray wire in the boat wiring harness for the SND pin.
Set the selector to "12p"

 

[HighTrim]

Re: Tach Issue (1985 Evinrude 70HP)

Lakester....

To try and explain it simply, tachometers read off the alternating pulses from the stator. Any of the leads from the stator charging portion can be used for the signal. The designated tach signal wire is merely attached to one of those. Tachs have rotary switches on the back that set it to different numbers of coils in the charging circuit, times two because there is a positive and negative pulse for each coil for each cycle. Tachs measure pulses. That being said, you need a tach that has the setting that you need designated on the rotary switch.

The BRP tach of the right model comes with a harness that you can plug and play as stated by JT. The Teleflex tachometers offer the harness as well.

http://www.iboats.com/Teleflex_Tach...d.246630--list_time.1199576059--view_id.40245

Or you can easily wire most tachs that have the correct settings on the rotary dial of course, by either going directly to the ignition switch or by cutting into the main harness.

 

[ezeke]

Re: Tach Issue (1985 Evinrude 70HP)

the link does not work HT

 

[HighTrim]

Re: Tach Issue (1985 Evinrude 70HP)

Ty Ezeke, fixed it.

 

[ezeke]

Re: Tach Issue (1985 Evinrude 70HP)

The correct OMC/BRP kits have the harness in them. They cost less than buying the aftermarket parts separately.

 

[jtexas]

Re: Tach Issue (1985 Evinrude 70HP)

just noticed the question about temp sensor in the original post...it's near the top of the cylinder head with a tan wire coming out of it. It should be connected to the warning horn located in the control box, through the main wiring harness. Test procedure: there's a rubber sleeve on the tan wire a few inches out from the engine; with the key in the "on" position, peel back the sleeve and touch the wire to the cylinder head, the horn should sound a steady tone.

 

[rannrupnorth]

Re: Tach Issue (1985 Evinrude 70HP)

Hey Gang
I just got back and saw all the replies..... This is great stuff and I'm positive it will work. I'm real glad to know that I can do this stuff.
Thanks a TON for the info, help, and prompt replies.

Take care and Happy New Year.