Since my P15 doesn't spend any time on dirt roads, and the oil-bath filter is sort of a pain to service, I decided to convert it to a paper filter. I did a lot of searching in the forum archives but the threads I found were several years old and most of the photos can no longer be accessed. I took photos of the method I used in the conversion so current and future members will be able to get ideas about how to do the conversion.
We need a filter element that has the proper diameter to drop into the recess in the bottom of the lower filter bowl. The height of the element isn't critical, I suspect if it is at least three inches high it can accomodate the torrent of air roaring down the throat of the one-inch bore of the carb. ?
At my local family-owned auto parts/lawn equipment dealer I found a Kohler filter for some sort of lawn machine that was a perfect fit.
A cap for the filter was cut from 1/8" aluminum, but any metalic stock would be fine if it is fairly stiff.
The top half of the old filter must be modified to accomodate the new paper filter. I used tape to establish a cut line on the upper bowl.
The cut-off wheel easily cut the bowl and the old fiber element was set aside.
I put the modified top back on the lower bowl, made sure it was fully seated and took a measurement of the protruding end of the stud.
The top was removed, the wing nut run down to the measurement I had taken, and another measurement was taken of the space between the bottom of the nut and the filter cap. This indicates how long a spacer is needed to fill the gap between the cap and filter lid.
The top lid was placed in position, the wing nut run down snug and the new, oil-less filter assembly installed back on the carb. This mod retains the original appearance of the filter, nobody can tell there is a modern paper element inside.
A test drive proved the P15 is happy with its new filter and it should be good for many years of maintenence-free filtering.