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no fire on 1972 evinrude 100 hp

(Voltage Drop To Battery Capacitance Discharge)
( Pulsepack When Electric Starter Is Engaged)
(J. Reeves)

On the older Battery Capacitance Discharge ignition systems (1968-1972), the electric starter reaches a point, even with a top notch battery, whereas the starter will draw excess voltage/current/whatever which results in a voltage drop to the pulsepack. The cure is to purchase a diode which is capable of handling 12 volts and installing it between the starter terminal of the starter solenoid (NOT the battery cable terminal) and the wiring terminal that supplies voltage to the pulsepack.

The diode must be installed so that the current flows from the starter terminal of the solenoid to the pulsepack... NOT vice versa. When that diode is installed in this manner, when the key is turned to the start position, the voltage that is applied to the starter is also applied directly to the pulsepack via the diode effectively eliminating the voltage drop and energizing the pulsepack with the required voltage needed for its proper operation.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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(Battery Capacitance Dischage Powerpack Test)
Various OMC Engines - 1968 to 1972)
(J. Reeves)
Purchase a small 12v bulb at your local automotive parts store (the 12v bulb is to look like a flashlight bulb, not a headlight bulb). Solder two wires to that bulb, one to the side of the bulb (ground), and the other to the positive point. You might use a bulb of a somewhat lower voltage to obtain a brighter glow... just a suggestion.

Remove the spark plugs. With the key in the on position, make sure that you have 12v going to the pack at the terminal block (purple wire). Now, connect the ground wire from the bulb to any powerhead ground. Connect the wire from the positive point of that bulb to the powerpack wire that is connected to the coil wire on the terminal board (blue wire).

Crank the engine and observe that bulb closely (CLOSELY!). If that bulb glows even the slightest bit, the powerpack is okay. It may be a very dim glow... just so it glows! If it doesn't glow, the pack has failed.

Keep in mind, that type powerpack (Battery Capacitance Discharge) demands a top notch battery of at least 70 amp hours. Any less will, in time, cause powerpack failure.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
 
I pulled the Flywheel and found anti-reverse spring had been put under anti-reverse sensor. Therefore stop it from firing. Thanks for help.
 
Boobie said:
Like I've always said, It's the little things that will get Ya.
Click to expand...


Be nice if it was explained why the reverse cutofrf spring stopped his sensor from working. Thew only thing I can tell is a possible short on the Distributor sensor pickup.

My problem is that although I read 5.2 ohms across the sensor, and I read a change from 5.2 to 5.1 ohms when I manually turn the motor - it seems this change isn't enough to get the ignition amplifier to spark the coil. When I short the 2 wires from the amplifier , it sparks the coil a good healthy voltage. But from the distributor sensor I get those ohm readings and no spark.

I started as thread for MSf ignition conversion. All I have to do is prove the sensor ( if its a on/off type app or slight variation type ) and I think I am good to go. I may have to go pertronix since I can't readily find a base with sensors anywhere.
 
PegCity said:
Be nice if it was explained why the reverse cutofrf spring stopped his sensor from working./QUOTE]

PegCity... Start a new topic so that your question is not hijacked from another members post. Also your new post would be a new topic and entered at the top of the listing rather than to be burried here.

That engine can actually run backwards and the purpose of the Anti Reverse spring is to have it slam against what he is calling the Anti Reverse Sensor... actually a metal extension that is wired to the sensor which would short the sensor out, which in return kills the ignition.

Having the spring loop attached to that metal shorts out the sensor, therefore the ignition is non existent.
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joereeves said:
PegCity said:
Be nice if it was explained why the reverse cutofrf spring stopped his sensor from working./QUOTE]

PegCity... Start a new topic so that your question is not hijacked from another members post. Also your new post would be a new topic and entered at the top of the listing rather than to be burried here.

That engine can actually run backwards and the purpose of the Anti Reverse spring is to have it slam against what he is calling the Anti Reverse Sensor... actually a metal extension that is wired to the sensor which would short the sensor out, which in return kills the ignition.

Having the spring loop attached to that metal shorts out the sensor, therefore the ignition is non existent.
Click to expand...


Does the Anti Reverse cutoff sensor have ignition power to it - or straight battery ? The guy threw me off since he implied the spring was wasn't sitting properly and perhaps shorting out the sensor pickup . The only thing the 2 sensors could have in common is in the amplifier -. On the johnson 72 , the Sensor pickup has the black white leads. They are only connected to an amplifier or pulse pack's magnetic pickup wires. I started an MSD topic - I will post pics and comments. Setup seems straight forward except for the issue of the magnetic pickup from the sensor.

A point I would like clarified - the anti reverse sensor should not stop the engine from running unless the spring is indeed shorting out the ignition. I've ordered a new spring, mine wasn't exactly new. Hopefully that is the solution, at worse, I am drilling down to the sensor itself - but I need to find out what its putting out when the Distributor trigger cycles.
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PegCity said:
joereeves said:
Does the Anti Reverse cutoff sensor have ignition power to it - or straight battery ? The guy threw me off since he implied the spring was wasn't sitting properly and perhaps shorting out the sensor pickup . The only thing the 2 sensors could have in common is in the amplifier -. On the johnson 72 , the Sensor pickup has the black white leads. They are only connected to an amplifier or pulse pack's magnetic pickup wires. I started an MSD topic - I will post pics and comments. Setup seems straight forward except for the issue of the magnetic pickup from the sensor.

A point I would like clarified - the anti reverse sensor should not stop the engine from running unless the spring is indeed shorting out the ignition. I've ordered a new spring, mine wasn't exactly new. Hopefully that is the solution, at worse, I am drilling down to the sensor itself - but I need to find out what its putting out when the Distributor trigger cycles.
Click to expand...



thought occurred to me, and that is dangerous. Since I don' t have the reverse cutoff sensor - green - hooked up to anything - is this putting into a kill ignition mode
Click to expand...
 
Omc had 2 types of packs..pulse and amplifier. The points model used a amp and the pulse used a sensor. The sensor works like a Hall effect sensor(sensor see"s object) and ohms/voltage drop fires pulse pack and reverse spring grounds sensor so no reading to fire pulse pack. To make the MSD conversion work you will need convert to points.
 
faztbullet said:
Omc had 2 types of packs..pulse and amplifier. The points model used a amp and the pulse used a sensor. The sensor works like a Hall effect sensor(sensor see"s object) and ohms/voltage drop fires pulse pack and reverse spring grounds sensor so no reading to fire pulse pack. To make the MSD conversion work you will need convert to points.
Click to expand...

This is what I was trying o figure out . What does the reverse cutoff have to do with the sensor trigger sending a pulse to the MSD. The cutoff only gets triggered if there is a kickback and the spring shrts it out to ignition.


The only thing I keep thinking is that the sensor trigger "HallEffect" isn't a strong enough signal to trigger the MSD . A short over the magnetic pickup wires on the MSD side causes the MSD to deliver what is required to the oil, problems.

Anyway to "amplify" that Hall effect - are you saying the MSD requires a definite open - close condition , in essence a short ?

1972's only came with a pulse - Seem Pertronix Ignitor kit is a possible conversion people have used to get around points.


Sorry I am not use to working on engine electricals but am intrigued. And thanks to all


Hrd to type on tis site.
 
Found this on MSD website.......
Hall effect sensor outputs a 5v square wave or digital signal, and the MSD needs a sine wave or analog signal. Plus as rpm increases the voltage increases in the magnetic pickup signal whereas the hall effect remains at a constant 5v max limit.
Click to expand...

Ordinarilly, the hall effect trigger would work when couplig that with the MSD 6 series ignition. What we have to look at is the output from that Hall Effect trigger being compatable with the input required to trigger the MSD ignition.

What the output signal from the HAll Effect needs to be to trigger the MSD ignition is a POSITIVE square wave with a 20° duty cycle at battery amplitude.

If that signal is opposite of what the MSD needs to see you will have to figure out a way to invert that signal in order for the signal to comply with what the MSD wants to see.
Click to expand...
 
faztbullet said:
Found this on MSD website.......
Click to expand...

Ths is what has me stumped. The MSD should be everyone's solution. It comes with both a points pickup - one wire and magnetic trigger pickup 2 wires. I know the sensor is within 4 - 6 ohms ( at 5.2 ) spec.

I know the sensor and metal rotor are gapped properly as per manual.

What I don't know is the voltage or impeadance the sensor snds to MSD

I don't know the min. MSD recognizes. For now d 5.1 every time the rotor crosses the sensor that's a miiniscule drop, which leas me t believe the sensor is shot. But can only confirm that when I know what it shld be outpttng
 
Strange that a 72 Distibutor component is outputting a digital signal - Also strange is that on one hand the MSD requires an analog signal / sine wave, then they say it the Hall trigger needs to output a square wave. Smthin doesn't jive.

Th statmen by MSD is ontradictory. Much preciate wll follow h htread o MSD's sit and ge clriicati. WATis WROn ith the typing on t site.
 
Start a new topic so that your question is not hijacked from another members post. Also your new post would be a new topic and entered at the top of the listing rather than to be burried here.
 
PegCity said:
PegCity said:
thought occurred to me, and that is dangerous. Since I don' t have the reverse cutoff sensor - green - hooked up to anything - is this putting into a kill ignition mode
Click to expand...


Sorry, I did start an MD Igiton Thread. Only posting here since cutoff spring installation solved a problem without a explanation, wcwas later given and learned something new But y all means, the MSDignition thread wil prove to be ore usefult others conteplatinga switch.

Posted on MSD to get their answer.
Click to expand...
 
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