06/17/2026
A day in the life of a small engine technician, part 13. Sometimes you think you've seen about all the things there are to see working on this stuff. But then along comes something you've never seen before just to keep you interested. A backpack leaf blower was presented as non-running. On pull over it was evident that compression was low, and a check with a gauge confirmed that. So, it was a dead duck but we wanted to see why as the gas was well mixed. I pulled the muffler and found the piston face looked good. So...maybe a broken ring? Either way, fix or not, I wanted to investigate. I disassembled the fan and housing from the engine and pulled the cylinder off. There were two grooves in the piston along the side where the transfer ports are, clearly from some sort of foreign object. Upon further disassembly, the cause was revealed. The needle bearing on the crank had failed. I've not seen one do this- it made the crank come apart into two halves. One of the needle rollers from the bearing had passed through a transfer port, causing the piston damage. New blower time! Equipment: Husqvarna 150BT.
