Mercruiser 5.0L Intermediately turns off

I have a 1999 Mercruiser 5.0 carb serial 0L330315. I've been having intermittent problems with the fuel system. Not sure if the fuel pump is going bad or issues with my carb or with any other component. When cruising, the boat shuts down immediately. The last five boating trips, I've had to disconnect fuel line from fuel filter up to fuel pump, pour the fuel from the fuel line in the carb and boat will start after reconnecting fuel line. That worked the last few times but now it takes a few times trying that method. I also notice when pumping throttle I sometimes saw fuel spray in carb and when fuel was spayed to carb, it would fire up at the time. All the other times when pumping throttle, never saw fuel sprayed in carb and figured it won't fire up. I did removed and cleaned fuel filter in the carb and replace 4 fuel filters in the last two months. I did tested fuel pump by removing fuel line and when turning engine over, fuel would pump but not sure what the actual pressure should be. Any suggestions?

Re: Mercruiser 5.0L Intermediately turns off

being carburated, you will need to have 5-7 psi of pressure after the pump. sounds to me like your having problems pulling the fuel from the tank. run through the tests in this link Don S. gave me. this will help figure out if there is a problem with fuel delivery up to the pump. once that clears then you should be able to use the same rigging you tested with to see fuel pressure after the pump. Start from the tank and work your way towards the engine. you may have to put in a temporary rig after the pump if your running all steel like you should be.

http://forums.iboats.com/showthread.php?t=283269