Yes, if the contact fell off, that's a very good reason for rough running. Check the flywheel again- - - - -I think the triangle is used for valve adjustment, not necessarily ignition timing. It will be close, but not entirely accurate for setting the ignition. There should be a ball, or a dot somewhere nearby.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!