Something has been happening recently. At least for the past few months and is becoming more frequent. What happens is on cold starts no problems. Only after I have run it for some time in our hot weather, I let it stand for a short period, and then restart it, there is a definite, loud clank. Like an engine knock but louder. It just does it once and then starts. Like the starter clicks in with a loud bang. Has anyone experienced this noise? I appreciate the help.