My W 30b does if fact self bleed. I had similar problems to you when I got my boat (and new engine) last year - the problem was the electric fuel pump had a loose connection.
The pump puts out 25 gallons a hour and you are using about 3/4 of a gallon of that, the rest gets recycled thru the tank and filters again. You are in fact polishing your fuel every couple of hours you run your engine - if the pump is running full time as designed. Finding the problem is difficult because as long as it runs every couple minutes you have enough pressure and fuel to run. It's when it goes a while that life sucks.
Check the 12v connection, tighten clean etc..then check the pump. If your really want to get fancy wire a light to the pump side of the connection and put it somewhere you can see it while the engine is running. Then you'll know if it's intermittent. Intermittent problems suck to find.
Eliminate the tank and pickup tube issue by getting a 5 gallon can of diesel and hose then feed the engine directly from there as a test, with the unused fuel going back to the same 5 gallon can (see below).
Troubleshooting possible multiple issues is simpler if you can eliminate one piece at a time.
It might be a air leak - easy way to check for that is to take off the hose that sends unused fuel back to the tank and put it into a bucket, run the engine and see if you have bubbles in that bucket (pre-fill the bucket with some fuel and put the hose under the fuel so you are not making bubbles with flow).
Westy's are good engines, but the electric pumps are somewhat exposed and prone to getting the connections knocked around while doing maintenance. The bad news is a replacement is 158 bucks (I've got two spares, I'll be glad to give you a discount). The good news is - almost any 12v fuel pump from autozone will do the same job for 40 bucks - damn, just killed my own sale.