Never had an issue with vapor lock. On the way back from Georgia a couple of weeks ago we decided to get some fuel before we crossed the line into Florida as gas is so much cheaper in Georgia. I guess I put 20 dollars into the boat before I saw the stupid 10% ethonal sign. Stopped the pump and filled it up in Florida at our non ethonal station. Last week on the lake it took forever for the boat to crank. She always did but I didn't like having to turn it over that much. I am amazed that little amount could have caused this issue.