1. Divide surface of trash screen into 25 equal squares
starting at the top.
2. Start engine and run it at fast idle.
3. Put air flow meter against the trash screen so it is
centered in a square and air flow is through meter in
the direction of air flow arrow.
4. Record voltage reading for each square not marked
out with an "X".
5. The combined total of voltage readings must be equal
to or greater than specification.