My LH thumb swings too much on seventh chord arpeggios

[Bob]

Anyone else have this?  And have/know of a solution for it? 

I noticed on chords, like an abm7th chord, that my LH thumb is swinging way out.  Too much I think.

If I use a fingering like this -- 2 1 4 3, 2 1 4 3, etc.  (I suppose someone might say it's the wrong fingering and that I should actually put my thumb on a black key, but even then I'm still wondering how to stop my thumb swinging with this fingering.)