Poulan 521017201  Gasket

The purpose of the Gasket is to seal connections between two or more mating surfaces. Gaskets can wear over time from overheating, abrasion, friction, improper lubrication, and high pressure. Your gasket may be damaged if the contact faces have a grazed surface, lacerations, and breaks. A damaged gasket can cause more consequential damage to your engine, gear case, or carburetor. Because gaskets must be the proper size to create a seal, we recommend gaskets are purchased from the OEM/Manufacturer.