Try a penny pinched between the primary and secondary gears on the right side of the engine. The penny won't damage the gears. Also be careful tightening that nut. The threads are only 10mm and not the hardest metal. Don't over do it. I wouldn't exceed about 150 to 160 inch pounds.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"