1992 Force 70 HP No Warning Chirp & Tach ?

[crappie14]

Four wires are found under the dash, Red, Orange, Purple, Black.
Red - 12 Volt Power When Key is on
Orange - ASSUMING Heat Alarm based on reading posting forum
Purple - ASSUMING Tach
Black - ASSUMING Ground

Red and Orange were connect to leads of warning horn
Purple and Black not connected to anything
All 4 of these wires and enclosed in a cable running to dash and I think go straight to motor but I haven't traced (new old boat)

That being said, First Question

On my other boats in the past when I turn the key on to start, I would hear a warning chirp, I guess telling me the work and wiring is good. I have tested the horn by disconnecting and touching to battery and it works. Does the 1992 Force 70 HP motor have this warning chirp or am I trying to fix something that don't exist? When I check voltage between the Red and Orange and turn key on I see a fraction of a second of .03 volts. With key on, Orange and Black have 12 volts.

Second Question,

This boat does not have a tach or has it ever had a tach. If the Purple wire is the tach feed and Black is the Ground, are these the only two wires needed to install a tach? If so I would consider installing one and if so can anyone recommend an affordable tach and what brands/type are compatible with Force?

Thanks in advance for your reply

 

[Frank Acampora]

Re: 1992 Force 70 HP No Warning Chirp & Tach ?

No Force engine ever had the diagnostic chirp.

Red is a common power source for all instruments. However, this particular wire should be powered ONLY when the key is in run or start position.

To wire the tachometer, you need red to power, purple to signal, and black to ground.

To wire the overheat warning, you also need red to one wire (or lead) and orange to the other wire. At the engine end, when the engine overheats, a simple bi-metal switch closes and goes to ground, allowing 12 volts to flow through the warning buzzer. SO, If you check red to orange, because of capacitance in the wires you will get a momentary small voltage. Since black is a common ground all the way back to the engine, if you check orange to black with red still connected to one lead of the buzzer, you will still get 12 volts. If you disconnect orange from the buzzer, then orange to black should show (0) volts

 

[crappie14]

Re: 1992 Force 70 HP No Warning Chirp & Tach ?

Thanks for the very prompt reply. It appears I was attempting to fix the "chirp" when it never existed. Only remaining question if someone has had good luck adding an economical tach, is what brand/type would you recommend. There is no dash hole to stick one in so it will have to either be one that can be installed in a console fairly easily by cutting a hole or perhaps a stand type surface mounted one that I have seen in cars but really don't ever remember seeing this type on a boat. It would need to be a fairly economical one or else I wouldn't be willing to spend the money. Thanks again.

 

[Boatdoc58]

Re: 1992 Force 70 HP No Warning Chirp & Tach ?

Forces do have a diagnostic BOOM though........:lol: It means it's broke !!!

 

[Frank Acampora]

Re: 1992 Force 70 HP No Warning Chirp & Tach ?

If it is the earlier Prestolite ignition you have no choice: You must use a 20 pole tach or a tiny tach. 20 pole tachs are getting difficult to find and I think only Teleflex made them.
I think later Mercury ignitions used a standard 12 pole tach and there are a couple of manufacturers like Teleflex and Faria.

Cutting the hole in the dash is a relatively easy job with a big holesaw. Just chuck it in a heavy duty drill. You may need to remove the steering wheel for clearance though.

 

[pnwboat]

Re: 1992 Force 70 HP No Warning Chirp & Tach ?

If you can post a picture of your ignition coils, we can tell which type of ignition system you have. The other way is the color of the coils. If they are kind of sky blue in color, then you most likely have the Prestolite 20 pole ignition system. If the coils are dark blue, almost black looking, then they are most likely the later Mercury Thunder Bolt 12 pole ignition system.

 

[Justinde]

Re: 1992 Force 70 HP No Warning Chirp & Tach ?

Go the tiny tach...... measures hours as well;-)