Walbro WT-813 high-performance carburetor. This is the carburetor recommended by Zenoah for upgrading your RC-style engine. Engines with the standard carburetor (WT-603, WT-668, etc) tend to experience a lag in low-end acceleration when tuned for peak power. The new carburetor includes an internal acceleration pump to allow faster recovery as the throttle increases. Carburetor specs: Walbro WT-813. 15.88mm bore, 12.7mm venturi, independent tunable high and low-speed jets. This carburetor does not have an internal choke.
Note: This carburetor now comes standard with a modified throttle shaft, so it will work perfectly in most R/C applications such as HPI Baja, FG Modellsport, etc. 

The stock part on the 
Zenoah G240 270RC Engines

Can be used on all Zenoah and CY RC engines