Husqvarna 372XP Crankshaft Seal O-Ring, Clutch Side

This Husqvarna 372XP crankshaft seal O-ring is used with the clutch side seal to help keep the crankcase sealed. It is a small, inexpensive part to replace whenever the clutch side seal is serviced.

Why crankcase seals matter

A two-stroke engine uses crankcase pressure to move the fuel charge. If air leaks in past a crankshaft seal, the engine runs lean. Signs include a high or hanging idle, a saw that will not tune properly and extra heat. On a 372XP that is felling and bucking all day, that can lead to a scored piston.

Seals harden with age and heat, and the clutch side seal also sees heat from the clutch and bar oil.

Small parts like this are easy to forget when ordering for a rebuild, and the saw can end up waiting on a five-dollar O-ring. Make a parts list from the Husqvarna diagram for your saw before you start, and order seals, O-rings and gaskets together. Store spare O-rings in a sealed bag away from fuel and sunlight so the rubber does not dry out or swell before use.

Service notes

Replacing crankshaft seals is a job for someone comfortable with engine work. The clutch and oil pump drive must come off to reach the seal. Install the new seal and O-ring without nicking them and follow the service manual. A pressure and vacuum test confirms the job.

If you are replacing seals, consider the flywheel side seal as well. More 372XP parts are in our chainsaw parts section.