Century 2 speed motor stuttering when starting on high speed

The pump in question. Just installed it today, along with a new mechanical seal and the correct 3/4hp impeller.

Low speed works normally, but high speed stutters/chatters/hesitates for a few seconds on spin up before it “catches” and takes off like it should. It’s wired correctly, and I don’t think it’s a power delivery issue since this is actually a downsize from a 1hp that was running fine.

It seems like the governor isn’t properly handing off from the start to run circuits. I’m guessing this isn’t normal and won’t just resolve itself, unless there is a break-in period or proceure that I’m not aware of. Is there anything to check or adjust that won’t void the warranty, or am I looking at an RMA?