It’s 40 seconds, blue smoke, the smoke after 40 seconds is not very obvious. I also saw the same situation on L2502 on YouTube, but after these engines are completely hot, there is no longer any smoke. I don’t know what is wrong with the new engine .I would think the newer model should burn even cleaner. It was around 40 when I tested the L2502 and I was very surprised how much it missed and smoked on start up. I have't been able to find any specs on the L2502 engine.