Yup, it's just a rich, new engine. That's all. After a few tanks it'll get friendlier. It won't go because it's very rich. Try leaning the HSN a touch before you start messing with the LSN. Leaning the HSN also leans the LSN.

Give it a shove when you take off, seriously. It''l help you get through the first few tanks of brake-in without stalling, until you can start leaning the engine out.