So recently I purchased a used GX160 engine. I go to start it and it starts fine. The issue is that it cuts of after a while. I found that slowing increasing the airflow lever and slowly increasing the throttle fixes this issue. I want to know if their is a good setting where I should keep the lever or do I have to continue slowly adjusting the choke until the engine doesn't die. This is my first question. Second: I noticed the the very edge of the keyway on thee shaft of the GX160 is chipped. Will this be dangerous or can I continue running. I don't want to buy a new crankshaft as that would be quite expensive. If I can continue running the engine as it is that would be nice. Any help is much appreciated.