M-18 bleed problem

[bhstech]

My 86 Cat 27 TR has a Universal M-18. I’ve owned her to 3 years now and put @120 hrs on the engine without a problem until last week. She had just under a ¼ tank of fuel in a 19 gal tank. I’ve run it down to this level before without a problem. I’ve check the gauge against actual measurement and it is fairly accurate. We motored out into the lake in a light breeze and found it wasn’t really enough so I started the motor again to go further out. We found some wind, and I was about it shut it down when the motor stalled without me doing anything. Not good. We sailed around for a few hours and I headed back. Fortunately, the wind was at our stern, I went wing on wing, dropped the sails just before entering the marina, and coasted into out slip and stopped. I even impressed myself. No bad for the first time trying that trick but conditions were perfect and I can’t count on that everytime.
I assumed it was out of fuel, so the next day I bought 2 gal on my way to the marina. I will have to take it out in a few weeks for the winter and next spring I was planning on cleaning the 30 year old tank and changing all of the filters and filling with fresh fuel. When I purchased the boat it had a full tank and the first year ran it down to about 2/3rds. The PO said the tank was probably half diesel and half fuel stablizers and biocides. To my surprise there was still fuel in the tank. I tied a clean pcs of white cotton to the end of the measuring stick and swabbed the bottom of the tank. Clean. I thought maybe suction line was blocked. I took it out and no it was OK. So now I definitely have air in the line I may as well change all of the filters instead of waiting till spring.
My fuel system, like most, has an electric fuel pump, to a Racor filter/separator to the spin on final filter on the engine. I changed all of them. The screen in the fuel lift pump had a tiny bit of debris but was far from clogged. The Racor and final filter are metal cans and I would have to cut them open so I don’t know about those. The plastic cup at the bottom of the Racor looked clean with a small amount of something like dust but very, very little.
Now for the bleeding. I followed Universal’s directions. They don’t say if the pump should be on or off. I opened the plug on the top of the final filter and nothing. I turned the ignition key and fuel began to flow and not air so I closed that off. Next the bleed valve coming off the injectors. It’s a needle valve coming off the injector bypass line and back to the final filter. I can’t move it clockwise or CCW because it’s the original and painted bronze like the rest of the engine. So I have to take some pliers to it to crack the paint. I start the lift pump and it ticks like crazy when I open it to the right. It starts to slow down and then I close it to the left. Engine starts, runs and stalls. I go through this process a few times and then it final stays running. I run it, at the dock, for about 20 minutes. Revving it up to 3000 rpm and down to idle (@800) I put it in gear, out of gear etc. Looks good. I turn it off and go to restart, won’t. I open the bleed valve off the injectors, lift pump clicks very fast and slows when I reclose it to a tick every second or just like before when the world was perfect. It starts, runs for 5 minutes or so at 1000 rpm and stalls. I bleed it again, restart and run for 20 min, or so like above and everything seems fine. I let the engine cool down. Won’t start unless I bleed again. This time I leave the bleed screw open all the way. Doesn’t seem to make any difference.
This has been going on for a week now. Yesterday we went out and ran it for about 10 mins to get out of the marina and into the harbor and raise the mainsail when it stalled again. We sailed for about and hour and back into the harbor, I bleed it and restarted and it ran fine all the way into the dock. This time I didn’t close the bleed valve all the way.
So, may question is: what am I doing wrong? I think the original problem was getting air in the line because I let the tank get too low and sloshing around, I sucked so air into the line. Does the injector bleed need to be completely closed? It would seem, looking at the plumping of the fuel system, it needs to get back to tank somewhere.
Sorry about the long post but I wanted to show everything I’ve tried and all of the symptoms. I don’t want to answer a bunch of replies with ‘been there, done that’.