Is my fuel pump bad??

[MoStruder]

Yamaha C115TLRW 1998 - I have replaced fuel separator, fuel line and primer from fuel separator to motor, pulled and checked the fuel pickup in the tank, removed the anti siphon at the tank, blew air through the fuel line from tank to fuel separator. When (if) I get it started I heard fuel that sound like it was surging or pulsating from the tank through what was then the anit siphon or check valve at the tank. Should this be happening or should the flow of fuel to a running motor be more constant?? Does it sound like the fuel pump is the culprit?? How do you tell??

thx...

[jb123]

there should be no restriction in flow
use an aux tank, hose,ball and FRESH gas, hooked to motor filter to isolate issue

[99yam40]

Test with a fuel pressure/vacuum gauge to see what is happening
could it be sucking air?

[MoStruder]

I believe I have removed any/all restrictions with the work I have performed. My question is should the fuel be surging at the tank anti siphon or a constant flow?? If it should be constant and I can hear it surging, is that an indication of a bad fuel pump?? thx.

[99yam40]

The magic words are" I believe"
testing will show if there is a problem

[Finisher]

there will be a surging noise at idle when the motor is running at the anti-siphon valve. that is normal. you need to test the fuel pump and there is a way to do that. but while the eng is running if you pump the primer bulb does it change the eng in any way?