DVA voltage readings for ignition components

[jmactacular]

I have a 1977 Johnson 25 HP (25R77H) pull start, that was ridden hard and put away wet.

Carb is rebuilt, everything moves, but no spark.

Next step is to test the resistance and voltage of the ignition components I had spark on the lower cylinder but not the top. So I removed both coils on the rear of the motor and cleaned up the block to create a good ground. i replaced the top coil and now I'm not getting any spark on any cylander. I have a feeling it might be the magneto sensor that tells the power pack when to fire, but I will test the voltage and resistance of the magneto coil, the magneto sensor, the power pack and the ignition coils.

2 questions:

Can someone tell me what the V and OHM readings should be for the ignition components for my motor? I have no battery connected so when OMC talks about the voltage across certain components I assume these are readings when the motor is being pulled over?

I bought a mastercraft 52-0052-2 multimeter and just need to know if the voltage readings that I will be taking from the meter can be compared to the ones specified by ignition manufacturers at the link below. I.E. are the voltages read on the meter DMA voltage.

OMC ignition troubleshooting
https://www.google.ca/url?sa=t&rct=...C6gRWNO4vnRi7ew&bvm=bv.49641647,d.dmg&cad=rja

Master craft multimeter
Autoranging Digital Multimeter | Canadian Tire

Thanks

 

[AlTn]

Re: DVA voltage readings for ignition components

you'll need a dva adaptor for your mm to check the voltages and yes they are measured when pulling the motor over...the CDI site that you have linked to will give you those values..seems like the first no spark to either is disconnecting the kill switch to the powerpack and checking for spark again..have you tried this? An extra pair of hands is really useful in checking the rope start models.

 

[jmactacular]

Re: DVA voltage readings for ignition components

Yes I have tried disconnecting the kill switch to no avail, but I will try again. I pulled all the pins from the power pack rubber plug and just plugged the pins into the adapter so i could use alligator clips to take readings while the stator was connected to the power pack, I think that's what your supposed to do. i tried reading the voltages last night and I was reading 0.25 volts from the sensor and about 160 v from the stator coil (under the fly wheel). But like I said I don't know if these values are correct because of my meter. Maybe I'll best some videos/pictures tonight.

.

 

[AlTn]

Re: DVA voltage readings for ignition components

were this mine, first things first, what are the compression numbers? these help determine how much you want to spend on this engine.

Second...the ignition components on the rope start models CD2 aren't unreasonable in my view. Sensor~$26, Charge coil~$25, Powerpack~$65, External coils <didn't price>.Charge coil readings w/o dva are ok, sensor coil should be .5v or greater and it may be that with a dva adaptor. You can take the voltage readings coming from the powerpack out to the coils and post that.

The powerpack seems to be the problem child in the CD2 ignitions,but testing is the only way to be certain. A dva adaptor or mm capable of making dva readings is necessary ,certainly for more sophisticated ignitions < much more expensive components >.

So, I'd check the compression first before spending any money on obtaining a spark. Any history with this motor or was it a purchase of a nonrunning motor?