When I change the air filter covers and filters, I like to inspect both the filter and the housing/covers. Sometimes you’ll find the filter is overly dirty in one area or suspiciously clean in another, suggesting dirty air might be getting around the filter.
You might also find a trail of brick dust on the housing where it doesn’t belong, suggesting the filters are poorly sealed, or that there’s a crack in the filter covers/housing. In these pictures you’ll notice that though the multi-stage, oil-impregnated filter has collected a lot of dust, there is still a lot of dust along the path that leads to the paper filter below. We had a bad seal somewhere, either between covers or with the first filter itself.
If any of the housings/covers are cracked, replace them. Brick dust getting directly into the combustion chamber will shorten the life of your brick saw from 10 years to about 10 days. Most construction supply stores have parts in stock or can order them. Replace all the filters, paper and otherwise. It’ll run about $15-20 per saw, but will help your saw last for years. Our newest saw is 3 years old (which replaced one that either got stolen or was dumped along with broken concrete and other spoils from a project – darn employees!), and our oldest is 9.
But before you install the new filters, thoroughly clean the housings and covers for the air filters. I’ll often use a toothbrush (sometimes with a little gas to loosen caked on dust) and/or air compressor.