Service kit for the Husqvarna 350BT backpack blower, with the air and fuel filters also fitting the 150BT built before 2022, the 150BF and the 350BF. Contents: air filter replacing Husqvarna 502844401, in tank fuel filter replacing 506742601, and one CMR7H spark plug gapped at 0.6 to 0.7mm, which is 24 to 27 thousandths of an inch. The air filter number also covers the 560BTS and 560BFS, and the fuel filter covers a wider group including the 170BT and 180BT. Two points to read before fitting. First, the spark plug. The 350BT takes a CMR7H, the short compact type, and that is the plug in this kit. Husqvarna specifies a BPMR7A for the 150BT, which is the longer 14mm plug, and the two are not interchangeable. So on a 150BT the two filters fit and the plug does not - pull the old plug and compare it. Second, the air filter. Husqvarna changed the 150BT element from 502844401 to 535316301 on machines built from about 2022, with the later one shared with the 345BT. This kit supplies the earlier 502844401, so compare the old element before fitting if your 150BT is a recent machine. Engine notes: both machines are two stroke and both take a 50 to 1 fuel mix at two percent with an air cooled two stroke oil. The 350BT is 50.2cc and is an X-Torq engine; the 150BT is 51.7cc and is not. They are two different engines, which is why the plugs differ. Both use a WYA-79 carburetor, Husqvarna 502845001. Fit the air filter dry, blow the housing out before the new element goes in, and check the fuel line and primer bulb for hardness while the tank is open.
- THE THREE SERVICE PARTS A BACKPACK BLOWER ACTUALLY WEARS OUT - Air filter, in tank fuel filter and spark plug for the Husqvarna 350BT. The two filters also fit the 150BT built before 2022, the 150BF and the 350BF. A blower lives in dust at full throttle, so these are the parts that take the punishment, and all three change in minutes with a screwdriver and a plug spanner. If yours is hard to start, bogging at full throttle or hunting at idle, start here before the carburetor.
- WHAT IS IN THE KIT, WITH THE NUMBERS - Air filter replacing Husqvarna 502844401, in tank fuel filter replacing 506742601, and one CMR7H spark plug, gapped at 0.6 to 0.7mm, which is 24 to 27 thousandths of an inch. The air filter number also covers the 150BF, 350BF, 560BTS and 560BFS. The fuel filter covers a wider group again, including the 170BT and 180BT.
- THE PLUG IN THIS KIT IS THE 350BT PLUG - READ THIS IF YOU HAVE A 150BT - These two blowers do not take the same spark plug. The 350BT uses a CMR7H, which is the short compact type, and that is the plug supplied here. Husqvarna specifies a BPMR7A for the 150BT, which is the longer 14mm plug, and the two are not interchangeable. On a 150BT the air filter and the fuel filter in this kit fit and the plug does not, so pull your old plug and compare it before fitting. Both types gap at 0.6 to 0.7mm.
- THE 150BT AIR FILTER CHANGED AROUND 2022 - Husqvarna moved the 150BT from 502844401 to 535316301 on machines built from about 2022, and the later filter is also used on the 345BT. This kit supplies 502844401, which is the earlier one. If your 150BT is a recent machine, take the old element out and compare it before fitting. Filters that do not share a number do not share a housing seat, and an element that does not seat lets dust straight into the engine.
- WHAT ELSE IS WORTH DOING - Both machines are two stroke and both take a 50 to 1 mix, two percent, with an air cooled two stroke oil. The 350BT is 50.2cc and X-Torq; the 150BT is 51.7cc and is not. Two different engines rather than two versions of one, which is why the plugs differ. Both run a WYA-79 carburetor, 502845001, so if the blower will not hold a tune on new filters, look there next. Check the fuel line and primer bulb while the tank is open, and fit the air filter dry.