Occasionally when I attempt to start the diesel engine the starter clicks but doesn’t engage. Battery is fully charged. when it clicks you can feel the starter trying to engage. I’ve replaced the starter with no luck. Sometimes if you roll the starter motor sprocket with your finger or screwdriver and try it again it will engage. When the starter works it seems to operate fine. The problem may occur whether the engine is cold or warm and in cold or warm weather. Electrical connections all seem good. Any suggestions Are appreciated.