There are different styles of venturi used on Marvel Schebler carbs, even amongst the 8N series runs. Assuming all of the 8N carbs use the same venturi style is a common mistake made, they do not.

Snap-in venturi - LOWER HALF

• The venturi locks into the bowl in the lower half
• It has retaining tabs or a machined shoulder
• You must install it in the bottom first
• When assembling:
  • Venturi goes in the bowl
  • Bowl gasket goes on
  • Top half is lowered and the venturi presses through the gasket

Drop-in venturi - UPPER HALF

• Gravity fit design
• Drops into the top casting
• Bowl comes up underneath it
• This is what most YouTube videos show

TROUBLESHOOTING

If your bowl won’t seat or align, you probably have a snap-in style venturi. Forcing it into place can cause the bowl to crack.

Double check:

• Venturi orientation
  • Small opening - up
  • Large opening - down
• Gasket fit:
  • The bowl gasket must not bunch up around the venturi
  • Light grease helps hold it flat during assembly