It sounds like a problem I had. All the same symptoms. After many tribulations I narrowed it down to the fuel filter. If you have one of the POS rectangular stock fuel filters, there may be a hairline crack, which causes fuel pressure prime to drop and you cannot start the engine except thru some very serious blue language. When the assembly gets warm, the crack seals allowing you to restart the engine. The only fix I know of is replace the filter assembly (base and filter). FYI, the Dodge M880 box filter is similar but won't work on the CUCV. My fix was go to junk yard and find an aftermarket fuel filter system (pre-filter and filter) off a wrecked 1985 or 1986 Suburban. I did not use the pre-filter, it's sitting in a box in the barn. The filter "base" accepts standard round spin on fuel filters and bolts to the firewall in the exact same position as the stock filter. I can't remember the maker of the filter, nor am I able to take pics right now but once I'm able, I'll post them. I may even have one of the spin on mounts, aka base. Once I replaced the filter assembly, I haven't lost prime in over 2 years. Even had the M1009 sitting for 6 months. Got in, turned the key on, let the glow plugs warm up and she's starts up after only 2-3 cranks. FYI, I did the dog "head something or another" mod, replaced all the glow plugs, replaced all rubber hoses that I could find, replaced the mechanical fuel pump, spliced in an electrical fuel pump and replaced the circuit card. Also pulled the fuel tank, cleaned same, ensured fuel sending unit worked correctly, replaced filler neck hose and vent hose... There's more but I can't remember all the repairs I made. Suffice it to say, I put a bunch of money into that rolling money sucking pot hole on wheels before I got it all done up right. Next step will be to get the suspension up to snuff but that's another story...
Fits Your Vehicle ACDelco/Fuel Pump Strainer