The air cleaners on all B & S engines are crap and have been so for the last 20 years since the old Power Builts when they abandoned the bolt down filters.
All ZTRs are dusty, some more than others and more when a collection system is installed.
Donaldson air filters are good providing they are original equipment by the engine manufacturer.
The few Donaldson air filters that I have seen that were installed as an accessory caused the engines to run an excessively rich fuel mixture.
Every engine manufacturer that installs them that I have looked at the parts manuals of, changes the jetting and or carbs to accommodate the Donaldson air filters restriction of airflow, check out the Kawasaki FS730V and the FX730V for example.
Donaldson designs and manufactures many of the small engine air filtering systems, the Cyclonic Air Filtration System used on Briggs Commercial Turf Series engines for an example.
I'll take the FX Kawi 730 in my ZTR over the POS B&S Pro Series "oil burner" that I had in my Simplicity.
Well worth the money....don't be penny wise and dollar foolish!
B&S has an engine that is every bit as good as the fx series Kawi. It's called the vanguard. . Comparing the fx series to the pro series briggs would be like comparing the fr series Kawi to the vanguard. I would be just as happy with the vanguard on my mower though
I have a 1998 Toro Proline 44 with a 16hp Vanguard engine. It is one of the best small engines I have ever owned. It takes a long time for the oil to start to darken, which, according to a mechanic friend, means the rings are still very close to "new" tolerances. That little motor has been quite a trooper....it has mowed a LOT of acres since I have had it. Besides that, it is quiet and smooth. The key is, though, I never let the oil go too long. I change it early when I can. Now I am anxious to see how many thousands of hours I can squeeze out of the new Commercial Turf engine on the 700Z I just bought Briggs is really talking this motor up quite a bit.