What is the correct Gap for a AC C75 for a Autopatrol 9? (Cat 20)

[Scott Kuehn]

I have looked everywhere on the web and old books, but can't find the correct gap for a AC C75 plug for our Autopatrol 9, (Same engine as a Cat 20).
I've seen .035 to .060.
Anyone have the true gap?

[edb]

Hi Scott,
magneto sprk plug gaps are usually set smaller/less than battery/coil ignition systems.

The good book for the Thirty says 0.023"
I usually use a hand hacksaw blade as my magneto s/plug gap.
These are usually around 0.025"
Cheers,
Eddie B.

[Soapy]

Your'e right on Edb. My father was an auto electrician from age 18, till he closed his shop at the ripe old age of 76, and he always said "all engines equipped with magnetos, require the plug gap to be .025
Ed