My dealer shop informed me that the filter ahead of the engine injector pump is strictly to protect that vulnerable close tolerance element in case something gets through the first filter and/or the booster pump comes apart. I was able to replace the filter under the cowling w/o removing it, but it was difficult enough that I moved it down under with the first filter. Even the hoses were the right length when reversed. I use steel body filters instead of the OEM plastic ones (more insurance from damage). I also installed a valve ahead of the first filter to eliminate trying to clamp the hose off. If I ever leave the tractor setting out somewhere I can turn off the valve and then defy someone to drive it off as the key is pretty easy to circumvent and they are all the same combination. I have never found debris in the second filter even when clogging of the first one stalls the engine. I am looking for a spin off cartridge type that will fit in the space down under, but it is not a priority. I do not have under body armor yet. Thinking on something easy to remove as I now have the first chewed up fan to replace.
Ron