testing magneto ignition
 

Quadra 75 with Magneto.
Been 6 years at least since I've fired it up. Rebuilt the carb.
Does not seem to ignite.
How can I safely test the ignition in my basement?
Pull plug and ground to case and spin the prop?

David

RE: testing magneto ignition
 

That would work. If you could spin it over with a starter, electric or spring would be best. The faster it spins, the stronger the spark.

RE: testing magneto ignition
 

Could not see a spark. Turned the lights down some too.
The black coil box has 2 wires that go to the engine case.
One directly to it, the other goes to it through the ignition switch.
Both test good continuity to the case.

Can that coil and spark plug wire be found at a local small machine shop or would I have to order one?
Also, I"m finging Allen head cap head screws that don't fit my allen tools.
It uses something between 1/8" and 5/32". Is that SAE or Metric? What size?
David

RE: testing magneto ignition
 

Put your tongue on the spark plug lead and flip the prop. If you have to crawl back down from the ceiling you will know you have a spark

RE: testing magneto ignition
 

Those wires kill the ignition if they are connected to the case. You kill the ignition by grounding it. Open the switch and test for a spark.

CR

RE: testing magneto ignition
 

On the Q-75, the lug on the mag coil nearest the iron core is grounded ... usually to one of the mag retaining bolts. The other lug, and a larger one located farther from the core is the kill connection and like Charley wrote, kills the engine when grounded.

Also, Q-75 mags like to have minimal clearances between the mag core pieces and the flywheel. I usually set mine between .006" and .010". Thats just the thickness of heavy bond paper or a thin business card. These will only make a spark when turned quite rapidly .... slow prop flipping won't produce a spark.

RE: testing magneto ignition
 

Doh!
You guys got it right. I did not label the kill switch when I built the plane. I was thinking of it as an On switch.
I realized that this morning as I was waking up and went downstairs to try it and I have a spark after all.

now I have a carb issue I think (another post)

RE: testing magneto ignition
 

[quote: Truckracer]
On the Q-75, the lug on the mag coil nearest the iron core is grounded ... usually to one of the mag retaining bolts. The other lug, and a larger one located farther from the core is the kill connection and like Charley wrote, kills the engine when grounded.
[/quote]

Thanks for the correction. I've not seen the Q-75. Should have confined my answer to how the switch operates.

CR