Yamaha 150 4 stroke - Need help

2004 Yamaha four stroke. Great engine up to now. 750 hours to date, run it every weekend. Recent problem with engine missing. I replaced the external fuel filter and the one under the cowling. No change. Took it to Marco River Marine for service. Changed plugs, adjusted throttle plates, removed and cleaned injectors. Says they tested all electrical components, but they do not have Yamaha service computer. 6 hours labor and problem not solved. Curious thing is it ran well for four hours after I picked it up. Now it seems starved for fuel. It will run for 2 to 5 minutes then slowly die. I can keep it running by squeezing the ball on the fuel line if I put it in neutral and catch it quickly. I can see the internal fuel filter canister is still full of fuel, so I assume gas is available, just not getting to the engine. Any thoughts would be greatly appreciated. Thanks.

[boats.net]

Pumping the primer bulb to keep it running usually means a fuel delivery problem, a restriction or air leak in fuel line going to tank or a bad fuel pump. Try running it on another gas tank like a 6 gallon portable and new fuel hose to see if helps.