Amazon has the Westinghouse WGen Series Outdoor Portable Generator Cover for $17 with free shipping on $35+ or with Prime. Universal fit cover protects from dust, dirt, moisture, and UV damage. For open frame generators rated up to 9500W. Measures 28.5" x 24.5" x 25".

Specifically designed for Westinghouse portable Generators: WGen2000, WGen3600v, WGen3600, WGen3600DF, WGen5500, WGen6000, WGen7500, WGen7500DF, WGen9500, and WGen9500DF.