I'm looking at ys 140's to replace my saito 180 in my yak and had a few questions. Between the 140 sport, the 140L and the 140dz which has more power? My saito is too inconsistent so I need something a little better. thanks.

It's either a 140 Sport or 160DZ. None of the other ones are made anymore. I'd go with the 140 Sport. More power than your Saito 180 by far.

well I'm also looking at used engines, would the 140l be a better choice than the sport?

I don't recommend used engines, but the L makes more power than a Sport. Only rub is the L could be somewhat finicky.