WT-644 OEM Walbro Cab PDF Print $12.00 SKU: WBR-WT-644 Carb WT-644 OEM walbro carburetor Add to Wishlist Add to Compare Back to: Walbro Carbs & Parts Description Walbro WT-644 high-performance butterfly carburetor with integrated choke. 2 jets (independent high and low), 15.88mm bore, 12.7mm venturi. Stock carburetor on the Zenoah G231PUM / G260PUM engines.