If the old washer was torn or scratched, the valve seat may need repair.

The valve seats were hardened so it could run on unleaded fuel.

If the valve seat is damaged, it can be recut using a special tool.

Without the presence of a lead compound, an engine's valve seats go unprotected.

Valves and valve seats are ground with special equipment designed for this purpose.

A loose valve seat usually falls out totally and damages the engine very quickly.

If the opening appears round, the valve seat is not replaceable.

These engines usually drop a valve seat with no warning, even if the engine has been well maintained.

However, if the valve seat is round, then it is a permanent one that cannot be removed.

Step 3: If the above steps don't solve the problem, check the tank ball at the flush valve seat.