I have always procrastinated changing of my secondary fuel filter on my Perkins 4.236 because of the mess of changing a cartridge style filter and then having to bleed the lines to get it started again. I've changed the primary very often and put off changing the secondary. I wanted to find a way to change from a cartridge to a spin-on type to make it easier and cleaner and found 2 ways to go; a replacement filter head from Foley Engines that was over $200 and an adapter that uses the existing filter head for less than $70 from BWParts.com: Fuel Filter Adapter Kit with Filter for Perkins 3.152 Motor - SKU: BW1296-K. This is made for the Perkins 3.152 motor but I confirmed the same size for my 4.236. Not sure if this will work for the more popular 4.154. My 4.236 used the filter #26561117 from Perkins which may be what other motors use and if so, should also be a candidate for a change.
I finished the install yesterday and ran her for 20 minutes without any issues. I did still have to perform a quick bleed of the system but didn't take more than a few minutes. I won't hesitate to change this easy spin-on filter (Napa Gold 3195) in the future, a lot easier and cleaner than the old way. One thing I will change in the future is the steel bolt that holds it on the head, changing to a stainless bolt at next filter change.