Suzuki xl-7

The purge valve only activates when your tank drops below 1/4 and due to the electric pump inside the fuel tank it would be wise not to let it go below 1/4 at any rate purge valve malfunction due to running regular fuel which is full of paraffin causes a varnish on the valve, if you have access to a scanner you can manually activate it several times and that may make it unstick