Engine runs 10 minutes then stops

[hugosalt]

Eje, Would seem you have isolated problem to your "secondary filter" (filter mounted on your motor).
I do not have my service manual for my 3 GM in front of me as it is on the boat, however
I consider myself somewhat familiar with said fuel filter and don't remember a "nylon"
gasket on the bleed screw that you refer to in post #9.
I do believe that there are or should be what I call "copper crush washers" in several spots and they should be considered consumables. Thinking ?? that your nylon gasket
may be in place of a copper crush washer.
Again I don't have my manual in front of me but likely a diagram is on line.
A quick search turned up Yanmar parts #s
23414 08 0000 or
23414 12 0000 (or both think there are several different sizes on filter)
In any case changing out any of these copper washers on your filter will be cheap and easy next step in troubleshooting problem.
Hope this helps.