Does anyone know the correct spark plug gap for my '80 Sting 440?
It has CDI, not points.
My Scorpion service manual says .020, but that is for Cuyuna engines with points.
I have a Cuyuna engine service manual that is specific for engines (with CDI), used in ultralight planes. It says to gap them at .035-.040.
The ultralight engines are de-tuned with different timing for lower HP and lower RPM.
So that's why I'm wondering what the correct gap should be.
I'm thinking gap should be .035-.040, for CDI engines.
Would it matter if the ultralight engines are timed different as far as plug gap is concerned?

Thanks for any info!

according to a manual I have it says for CDI gap at .45mm or .018 inch. for the non CDI says .4mm or .016 inch.

Thanks doo rider,
What manual did you get those specs from?

:D I have used .020" with no problems on all my plugs CDI or points :D

ok, what is CDI and how can i tell if i have points or CDI?

im pretty new at working on these things.. sorry for the dumb question..

my 1979 whip 440 will start buy die after about 10 seconds... does this sound like a sparkplug issue?