Carburetor Set MXT Standard 19 mm complete with E-Choke compatible with GY6 50-80 cc QMB139 QMA139

This MXT standard carburetor with 19 mm nominal diameter is designed as a complete replacement carburetor for GY6 4-stroke engines in 50 to 80 cc versions. As a diaphragm carburetor, it supports smooth mixture preparation in everyday operation. The electric choke is pre-installed and allows for automatic cold starting.

Product features:

• Carburetor in 19 mm version
• Diaphragm carburetor with integrated accelerator pump
• Complete with electric choke
• Pre-installed jets
• Ready for installation

The diaphragm control stabilizes fuel dosing under varying engine loads, while the integrated accelerator pump delivers additional fuel temporarily during rapid throttle opening, thus supporting throttle response. The pre-installed E-Choke automatically takes care of the cold start enrichment, improving starting behavior in cold operation, provided the electrical connection matches the vehicle. Overall, the carburetor is intended as a ready-to-install replacement solution, where fit and basic jetting must match the existing intake and air filter system.

Technical details:

• Design: Diaphragm carburetor
• Nominal diameter: 19 mm
• Choke: electric
• Main jet: 80 or 85
• Main jet type: 6744
• Idle jet: 33
• Diameter main jet: 4 mm
• Throttle slide diameter: 15.5 mm or 17.9 mm
• Intake flange connection: 28 mm
• Air filter connection: 38 mm

For compatibility, the connection sizes of 28 mm at the intake and 38 mm at the air filter are crucial, as air leaks or tensions directly affect mixture formation and idle. The specified jet sizes and the main jet type 6744 define the basic tuning, which can be adjusted depending on the air filter condition, exhaust, and displacement within 50 to 80 cc. The possible variations in main jet and throttle slide diameter indicate that a comparison with the existing carburetor before installation is advisable to avoid deviations in tuning.

Vehicle and model compatibility:

• Suitable for GY6 4-stroke engines
• Compatible with QMB139 and QMA139 engines
• Application range 50 to 80 cc
• Commonly installed in hardware store scooters and Chinese scooters

Note: Since this is a universal component, modifications may be required depending on the vehicle version.

Installation and application notes:

• The carburetor is delivered ready for installation. Connect the electric choke to the existing connection. After installation, adjust the carburetor and check engine operation. Adjustments to intake or jetting may be necessary. Correct adjustment is crucial for clean engine operation and reliable function.

In operation, starting behavior, idle stability, and throttle response directly depend on whether the E-Choke is correctly controlled and the intake system is airtight. After installation, the adjustment and, if necessary, modification of the jetting ensure that the mixture preparation matches the actual engine and air filter configuration, and that the 4-stroke engine revs cleanly under load.

Note on checking before purchase:

• Please check before purchase whether the engine, connection sizes, and carburetor type match the existing version. This product is not vehicle-specific. Additionally, check the connector type or connection of the electric choke on the vehicle.

OEM No. for comparison purposes:

• 0/500.718.0001
• 16100-LDC8-E10

Short info: Carburetor - Installation, adjustment & tuning

Installation: Install carburetor without tension, check intake and gaskets for air leaks, adjust throttle cable for smooth operation, ensure fuel supply (gasoline, oil, and vacuum).

Basic setting: Mixture screw usually 1.5 - 2.5 turns open, idle screw for stable idle adjustment, always tune the engine warm.

Tuning:

• Main jet = full throttle / high load
• Needle position = partial load & acceleration
• Idle jet = idle & starting (should not need to be changed in most cases)

Control: Check spark plug condition

• white = too lean
• black = too rich
• brown = optimal

Important: After changes to air filter, exhaust, or cylinder, a new carburetor tuning is mandatory.

About the manufacturer MXT

MXT is the powerful own brand of Heavy Tuned and stands for high-quality replacement and tuning parts for motorcycles, scooters, and moped scooters.

As a reliable alternative to OEM parts, MXT offers a wide range of cylinder kits, carburetors, and crankshafts to variator components, body parts, and batteries. The products impress with solid workmanship, precise quality, and a strong price-performance ratio.

Ideal for riders looking for durable replacement parts and tuning parts for many vehicle models.