Stens 615-740 Primer Bulb Replaces Walbro 188-12-1 Homelite UP04802 Walbro 188-14-1 Stihl 4133 121 2700 Walbro 188-14 188-12 Echo 12318140630 Shindaiwa 20036-81670 Primer bulb replacement Not compatible with greater than 10-Percent ethanol fuel For small engine outdoor power equipment; stens part number 615-740 Inside diameter .579-inches