This primer bulb (primary cap / fuel syringe) with a closed plastic housing is used for manual priming and delivery of fuel from the tank directly into the carburettor before starting a cold engine. Pressing the flexible silicone cap creates a thrust that removes air from the system and fills the built-in chamber with fuel, enabling quick and reliable starting of the machine on the first attempt. By choosing this quality kit you successfully prevent the risk of false air being drawn in through cracks in the old bulb, which usually causes unstable idling, engine choking when the throttle is applied and hard starting. Installing the new primer bulb and its housing requires careful cleaning of the mating surface on the carburettor so that the seal sits perfectly. When connecting the fuel hoses, pay attention to the layout and diameter of the connection nipples (Ø3.25 mm) so that the fuel does not circulate in the wrong direction or the joint is not loose. The screws that fix the housing with a 24.5 mm spacing should be tightened moderately and carefully, because excessive force can deform the plastic housing and cause permanent fuel leakage at the joints. Key characteristics Part type: Primer bulb with housing (kit) Manufacturer: high-compatibility aftermarket part Carburettor model: Walbro WT (closed type) Mounting hole spacing: 24.5 mm Overall height: 31 mm Connection nipple diameter: Ø3.25 mm Catalogue number: 23239 Compatible models Machines with Walbro WT series carburettors: Engines of trimmers, chainsaws and blowers that use Walbro WT carburettors (Stihl, Husqvarna, Partner, McCulloch, Villager, etc.)