wiring on 89 merc 115hp

[jdogg#1]

just got a 89 mercury 115 hp and im getting no spark and trying to figure out the kill switch wires what wire goes to what

 

[achris]

Re: wiring on 89 merc 115hp

just got a 89 mercury 115 hp and im getting no spark and trying to figure out the kill switch wires what wire goes to what

Kill circuit wires are black/yellow... Disconnect it from the switchbox and recheck for spark...

 

[jdogg#1]

Re: wiring on 89 merc 115hp

i just have the motor on a stand an the guy igot it from just cut the harness off so im a little lost. what do i do with the yellowand black wire.ground it or what

 

[achris]

Re: wiring on 89 merc 115hp

Grounding the black/yellow will stop the engine. In order for the ignition system to spark, the black/yellow must be open circuit. Be careful, because when the engine is running that wire has about 400 volts on it.... and it really hurts when it bites!

 

[jdogg#1]

Re: wiring on 89 merc 115hp

disconnected blackyeliow wire still no spark

 

[achris]

Re: wiring on 89 merc 115hp

Now you need to start troubleshooting the ignition system. If you have a DVA meter great... Easy. If not, not so easy. We can do a few resistance checks. Refer to the circuit below....

Check that the 2 stator windings are not short to ground, and that they are also not open circuit, same with the triggers (although I consider it VERY unlikely you have both triggers out).

I'm in the process of designing a small and cheap add-on DVA adaptor for a standard multimeter. Stay tuned.

 

[jdogg#1]

Re: wiring on 89 merc 115hp

i have a power prope will that work

 

[jdogg#1]

Re: wiring on 89 merc 115hp

it looks like the red wires are grounded

 

[achris]

Re: wiring on 89 merc 115hp

it looks like the red wires are grounded

That's with them disconnected from the switchbox, yes....

That could stop spark. Check for spark with them disconnected. If you get spark, you're in for a new stator.... sorry...

Chris........

 

[jdogg#1]

Re: wiring on 89 merc 115hp

no they werent disconnected the aren't groundd al looks good there

 

[achris]

Re: wiring on 89 merc 115hp

In that case it's time to break out the DVA.... With all wires connected to the correct terminals... While cranking check for 200-400 volts across the low speed stator (blue and blue/white). If you have that, then the problem is the switchbox.... If not, disconnect the blue and blue/white wires and see if you get anything across them while cranking.

Chris.... (still working on the DVA circuit)

 

[jdogg#1]

Re: wiring on 89 merc 115hp

the highest i got was around 50 volts

 

[achris]

Re: wiring on 89 merc 115hp

the highest i got was around 50 volts

Is that with a DVA? If not, then it's not a valid reading....

 

[jdogg#1]

Re: wiring on 89 merc 115hp

no i will get one torrow thanks for the help

 

[jdogg#1]

Re: wiring on 89 merc 115hp

ok irechecked about 30volts with the blue wires connected and 250plus disconnected

 

[achris]

Re: wiring on 89 merc 115hp

ok irechecked about 30volts with the blue wires connected and 250plus disconnected

That would suggest a faulty switchbox...

 

[Texasmark]

Re: wiring on 89 merc 115hp

gers out).

I'm in the process of designing a small and cheap add-on DVA adaptor for a standard multimeter. Stay tuned.

We just went through that last week: Diode rectifier with a preferred 1kv. Capacitor of .47 UF up to whatever suits you...seems 2.2 ufd electrolytic is common.....Leakage resistor of 1 or more Mohms, value not really critical.

Meter goes to the DCV scale. Diode rectifies the incoming pulsed bipolar signal, capacitor charges to the peak value, resistor keeps the capacitor bled down (slowly) so that if the incoming signal drops in value, the meter can measure it.

Mark

 

[achris]

Re: wiring on 89 merc 115hp

We just went through that last week: Diode rectifier with a preferred 1kv. Capacitor of .47 UF up to whatever suits you...seems 2.2 ufd electrolytic is common.....Leakage resistor of 1 or more Mohms, value not really critical.

Meter goes to the DCV scale. Diode rectifies the incoming pulsed bipolar signal, capacitor charges to the peak value, resistor keeps the capacitor bled down (slowly) so that if the incoming signal drops in value, the meter can measure it.

Mark

That exactly what I had in mind, just sitting down and doing the math for values. Then I'd do a nice drawing, and maybe some photos, so people here can build it....

I'll use a 1N4007, and a 'greencap' (1000v rating) and a resistor so the bleed off is about 3 seconds. All mounted in a small box, or even better, encapsulated in epoxy.

Still working on details... And a few (thousand) other things around the house, and fixing my boat, and some friends boats... Maybe this explains why I'm not getting a lot of sleep

Cheers,

Chris.....