Can i test fuel system out of the engine? I took everything out, following service manual info, fuel cooler,pump,regulator,hoses from filter and hose going to carb. Its a 1998 5.7 efi.Changed a few damaged o-rings, pump energizes, regulator is dry, When i had system in the boat i disconnected fuel line going to carb. turn key to on position and no fuel came out of hose but i could hear pump energizing. is this right?

Ok so what do you have 5.7 EFI or 5.7 carb "I disconnected the fuel line going to carb" your words.

You have to fill up the fuel filter completely with fuel to help with a possible stuck check valve in the electric fuel pump, this helps moves fuel thru instead of air in the filter. If you removed any fuel system parts on top of - you need to prime the complete fuel system with fresh fuel before trying to start motor. You have air in the fuel system hence prime it first. A electric fuel pump without fuel running thru it will or can hurt its longevity. Merc has Service bulletins about this as well. it basically the same info as I am giving you.

How do you prime the fuel system?

what do you have carb or EFI with the Gen II cool fuel. ?

It's an EFI GEN II, TBI, twin injectors above carburetor with cool fuel system

The fuel filter is full, do I have to fill the lines too? I thought after starting engine several times pump should have filled system with gas.

It's not a carburetor, it's a throttle body

Yes you are right, its a TBI, excuse my ignorance it just looks like a carburetor to me.

well to have the truth be told is (TBI) is really 1980 to 1985 auto side old tech that boats used up to 2001. Unreal. Also really its a glorified carburetor. In boats this fuel injected set up only offered a tad bit crisper throttle response and easier starting of the engine compared to carb. That's it. It did not offer better fuel mileage and a few cases it was worse than carb engines = hp to hp apps. I have the tests that Sea Ray did with their bowriders on fuel consumption comparisons back in the late 90's.

If you got your motor started and running then fuel delivery should be all primed..