Help 4.3 fuel issue or in tank

[90 stratos]

Looking for help to a on going problem , Here is what is happen and what I have tried, looking for any idea's

The back ground

I bought a 90 starcraft majestic 4 years again , I bought it with a bad motor . I started looking for a 4.3 to replace the bad one, but the only thing I could find was a motor that had a electric fuel pump block mid 90's . so i ordered a carter pump put it on and the issue I am having is that the fuel stops drawing from the tank. I have add a 2nd pump in front of the tank behind fuel/water filter as a booster pump ,but it did not help still dose the same thing. i have drained the tank ,changed the pick up tube pulled the screen in it ,removed the anti s valve. But nothing seams to help , the vent is free and clear. It seams like I get vaper locked but not sure. I have to suck the gas from the tank through the pump to reprime it and So times it will run for a few hour to a few min's. I have ran it of a portable 3 gal tank this weekend and it ran out great. I unhooked it primed it and it ran for less then 5 min's and die I reprime it again and drove it back to the dock. Anyone out there have any ides. I would love to hear from you.

Thanks

 

[jerryjerry05]

The anti siphon valve might be too strong for the pump to draw through.
The new pump a marine electric pump?
How far away is the pump from the tank?
The pump has "pressure" but not a lot of "pull"
The hose is it soft?

 

[luremaker]

jerry
The anti siphon valve is pulled out , yes it is a marine pump, and I am about a foot or so from the first pump and about 2.5 from the 2nd, yes the pull of the pump is low but pushes very well, and I am not sure on the lines but I am going to change the rubber on this week

 

[MikDee]

Put a new anti-siphon valve back in! It acts like a one way check valve, letting fuel go through, but not go back! This should help keep a reserve of fuel in the lines to the fuel pump.

 

[90 stratos]

MikDee
I understand that but it dose not change a thing while I am running , I just run"s out of fuel.at running speed or trolling speed the issue started when the newer motor was put in and went from a std fuel pump to a electric pump and i have had 3 different ones in there, could the lines from the fuel/water sep be to small I used tranny line to fab the new lines?

 

[90 stratos]

MIkDEE

This will make no differance while the boat is running ,it would still be drawing fuel from the take at lease it should

 

[MikDee]

Alrighty then, check out your tank vent real good, if not enough air can get in, not enough fuel can get out.