Oregon 50-659 Replacement Carburetor For Tecumseh 640349. OREGON is a world leader in saw chain, guide bars, sprockets and forestry accessories and a leading manufacturer and supplier of lawn mower blades and other outdoor equipment parts. They offer more than 8,000 quality products-among the widest selections of first-class, innovative products available in the industry. Note: Put a genuine Tecumseh bowl o-ring (631028) around the bowl to the body to get it to quit leaking.