2005 mercruiser 3.0 TKS fuel problems I think??

[bman440440]

ok here is what is going on.... problem --->engine will not keep running with out a LOT of throttle when starting and to keep it running... thought we had a problem with the anti siphon valve (we did open the filler cap just incase it was a clogged vent line)... so we disconnected the fuel line from the boats tank and hooked it up to a 6 gall aux tank... runs great on the aux tank... ok go to replace anti siphon valve and it breaks off so we ordered a new fuel tank pick up with valve and install it... same problem... so I unscrew the new pickup assembly and shove the fuel hose down into the tank to the bottom.... after the fuel get to the carb it runs great no issues... so I take off the anti siphon valve from the pick up and reinstall into tank... the problem is back again... what could be causing this??? could it be a weak fuel pump?? BTW there is no fuel in the clear line that goes to the carb from the pump when the diaphragm fails... HELP!!

 

[Bt Doctur]

Does sound like a weak fuel pump not being able to draw from the anti-syphon

 

[bman440440]

Does sound like a weak fuel pump not being able to draw from the anti-syphon

I even took the anti syphon off and put a regular barb connector on the pick up and still has the problem... could it be that it is so weak that the 90 degree turn is just to much of a restriction?

 

[Stargazer1967]

Maybe a clogged vent? Try opening gas cap and see if that helps, If so then I would suspect the vent.... Sorry just saw that you already tried that.