The B3350 was the problem child. They tried to make a simplified emissions control system, which was different than every other tractor they make. It didn't work well. To their credit, they stood behind them and fixed them. But only that specific model has had those problems.
Plenty on here will tell you that any emissions systems at all will always be a problem. That hasn't been my experience. Ultimately, if you want to avoid emissions systems you need to buy a tractor under 26hp, if you need more than 26hp, then you'll get emissions systems. The L3301 is as good as any. The L3901 has the same engine tuned for more power - I'd be tempted to make that step if I was going to the L3301. If your application can use that extra HP.
