Custom Brass Carburetor Plug Screw Specs – Finalized 
Application: 
• Vehicle: 1987 Nissan Sentra B12 
• Engine: E16S 
• Carburetor: Hitachi DCR306 • 
Purpose: Bowl plug screw (not a jet, no center hole)
Thread Details: 
• Thread Type: M5 x 0.8 (ISO Metric coarse, right-hand, 6G) 
• Major (outer) Diameter: 4.8 mm 
• Thread Length: 3.8 mm 
Head Details: 
• Head Type: Flat-top slotted screw (no knurl, no markings) 
• Head Diameter: 7.1 mm 
• Head Thickness (Height): 2.2 mm 
• Slot Width: 1.5 mm 
• Slot Depth: 1.2 mm 
• Slot Style: Single straight slot (standard flathead screwdriver)
Shoulder & Chamfer: 
• Unthreaded Smooth Shoulder - Length: 1.2 mm 
• Chamfer Angle: 45° (precise sealing angle) 
• Chamfer Length: 1.2 mm 
• Sealing Style: Brass-to-brass taper seat — must seal air-tight with no gaske
Overall Length: 
• Full End-to-End Length: 8.7 mm
Material & Tolerance: 
• Material: Soft brass (machinable, corrosion-resistant for fuel contact) 
• Surface Finish: Clean, burr-free 
• Tolerance: ±0.05 mm on all dimensions (2 thou)
Special Notes: 
• No hole or orifice in center (this is NOT a jet) 
• Screw is plug-style and must seal under vacuum/fuel pressure 
• Designed for Hitachi DCR306 carburetor bowl plug – 
replaces factory brass screw