I want to adjust the sensor air gap in my Volvo-Penta I/O. The Clymer's
manual says use a non-metallic feeler gauge (note: non-metallic, not
non-magnetic). I've checked all around and cannot find one. A google
search of non-metallic feeler gauge bring up references to it's use for some
autos, but no sources. Snap-Ons online catalog does not list one.

Any idea where to find one? Thanks.