Mercury 60hp ignition system

[twostroked]

I have a mercury triple 60hp '86 or so s/n 0A982217<br /><br />One day last week, it didn't start.<br />A new set of plugs became fouled with raw fuel when cranking.<br />I checked the spark with an adjustable gap type tester.<br />No spark at 1 2 or 3 with the plugs in the engine.<br />When I removed the plugs (and cranking RPM increased) there was about a ".020 -".030 spark at best.....<br />I happen to have a fluke 97 portable DSO laying around and thought I might check out the stator, trigger, switchbox, etc.<br />I performed the following tests on the system with all components connected:<br /><br />scope settings:<br />timebase 10ms<br />volts/div 20<br /><br /> checked the stator output (from red or blu wire to ground) and it was > 80v p-p sin wave at cranking.<br /> checked between red and blu and got what looked like a 40v peak 1/2 wave.<br />(are these separate hi/lo windings?)<br /><br /> checked from the grn, grn/red, and grn/wht wires to ground (coil primaries) and barely got a 3 volt pulse of about 1 ms width cranking....<br /><br />volts/div 5<br /><br /> checked from brn, wht, and vio to ground (trigger?) and got about 5 volts or so cranking.<br /><br />Does anyone know the ballpark cranking waveforms for this ignition system?<br />I can't seem to pry this information from anyone repairing mercury in this area.<br /><br />Thanks for reading.

 

[ODDD1]

Re: Mercury 60hp ignition system

Well, I have never used a scope on a CDI system, so most i cannot answer...What i can say is yes 2 windings in stator...blue is low speed an red is high speed...we use a peak reading dc meter....you should have 180volt monimum at coil outputs[grn wires]....5volt is normal for a merc trigger,so trigger is ok...normal output on stator is 250+v on blue and 20+v on highspeed{red}.....will bet on a open low speed winding in stator....will give very low output like you have.....

 

[twostroked]

Re: Mercury 60hp ignition system

Thank you for the response. <br /><br />If you are reading 250v+ on a DC meter,would that mean the p-p ac output on the blue wire should be about 500v?.<br /> Is the meter you use a digital voltmeter with min/max captutre? (just trying to translate the waveform).<br /><br />What are the RPM thresholds of the red and blue windings?<br /><br />Does the switchbox actually select one winding or the other? i.e. would a cranking RPM above this threshold result in spark if the hi speed is ok and lo speed is open or shorting to ground? <br /><br /> I will order a new stator. <br /> <br /> Do you know the thread dia and pitch of the flywheel removal tool?<br /><br /> When I get this SH*&BOX banging again I will post good cramking ignition waveforms.<br /><br />Thanks again.

 

[ODDD1]

Re: Mercury 60hp ignition system

Two stroked, yer gettin in to deep for me....last time i touched a scope was 20 years back....When it comes to test equipmennt on these systems digital/ scopes DVM's with capture many times lead you down the wrong path....we are working witha very dirty signal in a high RFI enviroment...the accepted ANALOG meter has a DVA [direct voltage adapter] scale built in...near as i can tell is a DC volt scale with a heavy duty buffer to give a readable needle movement......digital stuff is ok, dont get me wrong but i still an analog man at heart....switch over from low to highspeed coils approx 2700 rpm's...is a natural selection, one drops off voltage were other picks up.....