WCF service needs restart after some time to provide proper response....

I have a WCF service deployed as a windows service. I have a website that tries to connect to this service and call one of its methods. The service works fine and also responds with proper reply. However, after some time (mostly after timeout) when I call one of the methods in the service, it returns a timeout error. The error tells me to increase send timeout of the binding. However, that doesnt work. I have also tried increasing the 'MaxItemsInObjectGraph' in the 'DataContractSerializerOperationBehavior' for the endpoint. But still the same error persists. When I restart t开发者_运维技巧he service form the windows services, the requests are handled correctly. Again, after some time the scenario repeats. Expecting an answer for this soon. Thanks in advance.