GY6 50cc (139QMB) Vacuum Fuel Petcock M14x1.00

GY6 50cc (139QMB) Vacuum Fuel Petcock M14x1.00. Fuel tanks, petcocks, pumps and intake parts deliver clean fuel to your carburetor or injector. Built to fit GY6, GY6 50cc (139QMB). Shop more GY6 50cc Scooter Parts (139QMB) and Scooter Fuel System Parts.

Fuel starvation, leaks or a vacuum leak at the intake cause stalling and poor running. Match the hose sizes and mounting.

Product details

Restore reliable fuel flow with this vacuum-operated replacement fuel petcock. Designed for scooters with gas tanks mounted high in the tail section, this petcock uses engine vacuum to open the fuel valve automatically when the engine is running — and closes it when the engine stops, preventing fuel from flooding the carburetor. Fits the M14x1.00 coarse-thread tank fitting used across CSC models and the broad GY6 / QMB139 Chinese scooter platform.

Key Features

• Vacuum-Operated (Automatic): Opens with engine vacuum, closes at rest — no manual ON/OFF/RES lever required.
• M14x1.00 Thread: Correct coarse-thread fitting for high-mounted tail-section fuel tanks on GY6 and QMB139 platforms.
• 5mm Fuel Outlet Barb: Standard barb size for OEM fuel line connections on listed scooters.
• Integrated Filter Tube: Clear 62mm filter tube screens debris before it reaches the carb.

Compatible Models

• CSC go. and go. MAX
• CSC Bella Classic 50
• CSC Nitro Sport 50
• CSC Pug 50
• GY6 125cc / 150cc scooters (157QMJ-based) with vacuum petcock
• QMB139 / 139QMB 50cc scooters with vacuum petcock

Technical Specifications

• Thread Size: M14 x 1.00 (coarse)
• Nut Inner Diameter: 13mm
• Fuel Outlet Diameter: 5mm
• Filter Tube Length: 62mm
• Operation: Vacuum-operated automatic petcock

Important: Compare your existing petcock to the image before ordering — once fuel has passed through this part, it is non-returnable. This petcock does not fit Genuine Scooter Company models, which use a different thread pitch.

Specifications

• Fits: GY6, GY6 50cc (139QMB)
• Part type: Fuel System Parts
• Engine size: 50cc
• Condition: New

Fitment check

Compare this part with your original before ordering: match the size, connector or part number, and the position on your scooter. Not sure it fits? Contact us with your scooter's make, model and year and we'll confirm.

Shop more: GY6 50cc Scooter Parts (139QMB) · Scooter Fuel System Parts · GY6 Scooter Parts · Scooter Parts