Piston kit for Husqvarna 150BT, 150BF, 350BT and 350BF backpack blowers, 50.2cc, 44mm bore, replacing Husqvarna part number 502849601. Also fits the Jonsered BB2250, which is the same machine sold under a different name. This kit is for 2020 and earlier production. Husqvarna revised this platform and units built from 2021 onward may use a different piston, so match the serial number on the frame plate against the parts diagram for your exact unit if your blower is newer. This kit does not fit the 130BT, which is a 29.5cc machine with a 38mm bore and an entirely different top end. Scoring on these blowers is usually caused by dust getting past a poorly sealed or neglected air filter, or by an air leak at the crankshaft seals or intake boot, rather than by honest wear. Inspect the filter housing, pressure and vacuum test the crankcase, and fit a new cylinder base gasket before running the new piston.
- FITS HUSQVARNA 150BT, 150BF, 350BT AND 350BF backpack blowers, 50.2cc, 44mm bore. Replaces Husqvarna 502849601. Also fits the Jonsered BB2250, which is the same machine under a different name. A blower down on power, hard to start, or showing scoring through the exhaust port needs a top end.
- CHECK YOUR PRODUCTION YEAR. This kit is for 2020 and earlier production. Husqvarna revised this platform and units built from 2021 onward may take a different piston. If your blower is newer, match the serial number on the frame plate against the parts diagram for your exact unit before ordering. The serial number is on a plate on the frame, not on the engine shroud.
- NOT THE 130BT. That machine is 29.5cc with a 38mm bore and a completely different top end. Backpack blowers look alike from behind and this is the mix-up that costs a weekend. The model number is on the frame plate.
- DUST IS WHAT KILLS THESE. The air filter is the only thing between yard dust and the cylinder wall. If this piston scored, check the filter and the seal around the filter housing before fitting a new one, and look at the intake boot for cracks. A fresh piston in a machine still drawing dirt lasts one season.
- PRESSURE TEST BEFORE YOU RUN IT. An air leak at the crankshaft seals or the intake boot leans the mixture and scores pistons, and it will score this one the same way. Pressure and vacuum test the crankcase, fit a new cylinder base gasket, clean the muffler screen, and break it in at reduced load for the first few tanks.