oldguy,
I've been running our M25 without stabilizer since 1998, only add biobor and sometimes water displacement stuff. I have found diesel fuel doesn't "go bad" like gasoline. Just my experiences.
Have you checked to see if the fuel pickup screen has been removed from your fuel fill line inside the tank?
There's a handy "Critical Upgrades" topic that covers a LOT of M25 series engine issues that you may find helpful:
http://c34.org/bbs/index.php/topic,5078.0.html
One of our technical gurus has recently replaced his M25XP with a b (after over 5,000 hours on his original 1988 engine). I am sure he would be more than glad to help you out. As I've mentioned here on this board a number of times, our engine systems are almost identical. While our guru doesn't read any other boards than our C34 Forum, please feel free to join us there, post your question and I'm sure he'll respond with helpful suggestions.
Stu [just another "old guy"

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