I have 99 60hp mercury it starts and runs for 30 sec and dies new plug and gas line it has spark and gas in carb bowl after it dies it start back up do you think if its not mixing oil it would dies?

Yes, if the oil is not mixing properly with the fuel, it could cause the engine to seize and die after a short run. In 2-stroke engines like your Mercury, proper oil-fuel mixing is crucial for lubrication and preventing overheating. If you're not seeing oil in the fuel or if the oil injection system is malfunctioning, that could lead to the engine dying after a brief run. It's important to check the oil supply and any related components to ensure they are functioning correctly.