Husqvarna 372XP Decompression Valve (X-Torque)

This Husqvarna 372XP decompression valve bleeds off compression while you pull the starter, so the 70cc X-Torque saw is easier to start. A worn or stuck valve can leak compression while the saw is running or make starting a fight.

How the valve works

You push the decompression button before pulling the cord. That opens a small passage in the cylinder so the piston is not fighting full compression on the starting pull. Once the engine fires, combustion pressure closes the valve and it stays shut while you work.

Over time carbon builds up on the valve seat, or the valve gets knocked in a fall. A valve that does not seal causes hard starting, low compression readings and a weak saw. One that sticks shut makes the saw harder to pull.

Climbers and ground crew who start saws many times a day notice a bad valve quickly. If the 372XP suddenly takes more effort to pull or kicks back on the cord, check the valve before blaming the starter. Carbon on the valve tip is often the first problem, and it can come from a rich mix, poor oil or a lot of idling. Cleaning the valve sometimes helps, but a worn valve should be replaced.

Replacing it

With the saw cool and the top cover off, unscrew the old valve from the cylinder, clean the threads and seat area, and install the new valve to the torque in the service manual. Do not overtighten it into an aluminum cylinder.

If a compression test still reads low after a new valve, the problem is likely rings or the cylinder itself. Browse related chainsaw parts for top-end components.