Husqvarna 390XP Cylinder Gasket

This Husqvarna 390XP cylinder gasket seals the joint between the cylinder and crankcase on the big 88cc saw. Any time the cylinder comes off for a piston, ring or cylinder job, a new gasket goes back on.

Why a new gasket every time

A two-stroke engine depends on a sealed crankcase. If air sneaks in at the cylinder base, the mix goes lean, the saw races or hangs at high idle, and the engine runs hot. On a big-bore saw like the 390XP that is pulling long bars through hardwood, a lean condition can scuff a piston fast.

Gaskets crush and take a set when they are torqued down. Reusing one is a gamble, and the gasket costs a fraction of what the rest of the job does.

The 390XP is often the saw that comes out for big removals, large stump work and milling, so it tends to run hard for long stretches. That makes a good seal more important, not less. If the saw was scored from a lean condition in the first place, find the source of the leak before reassembly, whether it is a cracked intake boot, a tired crank seal or a clogged fuel filter. A gasket alone will not fix those.

Rebuild tips

Clean both mating surfaces carefully without gouging them, fit the new gasket dry unless the service manual says otherwise, and torque the cylinder fasteners evenly in a cross pattern to spec. A pressure and vacuum test after reassembly is the best way to confirm the engine is sealed.

If you are not set up for engine work, a Husqvarna dealer can do the job. More service parts are in our chainsaw parts section.