G'day MF,
Thanks Tyler. That link was informative but replace every three months? I don't think so Tim!
An old B&S Service Manual I have says to wash and re-oil foam filters every 3 months or 25 hours run-time, whichever occurs first. With the proviso that "Capacity of “Oil-Foam” air cleaner is adequate for a full season’s use, without cleaning, in average homeowner’s lawn mower
service. (Clean every few hours under extremely dusty conditions.)"
BTW, this B&S how-to does mention servicing of foam filters, but doesn't say how to do it;
https://www.briggsandstratton.com/n...se/how-to-replace-a-foam-air-filter.htmlFor a commercial workshop, I'd say replacement with a new element would work out cheaper, with their labour rates! And most mower owners don't really want to know about dirty jobs like cleaning air filters.
To elaborate on what Tyler has said, the oil gives the foam the ability to trap fine dirt particles, which dry foam can't do.
There are quite a few tacky foam filter oils on the market, as most off-road motorbikes have this type of filter. There are even water-soluble types available, which saves having to use mineral turps to wash the dirt out with.
