Fuel pump problem?

[gwhjr98]

Problem at high end RPMs.. engine runs rough WOT. Put pressure gage on fuel line. at idle PSI at 6... running WOT it dropped under 3. voltage did not drop on pump. Changed the fuel filter no change. this is on a 350 engine 4bbl engine. Is it time to replace the fuel pump?

 

[Bt Doctur]

Re: Fuel pump problem?

1 test run using a outboard tank
2 check anti-syphon at tank

 

[Don S]

Re: Fuel pump problem?

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

 

[gwhjr98]

Re: Fuel pump problem?

Thanks for the quick response.. Have not checked Anti-Siphon Valve but will.. is it located under the floor? What am I looking for in a defect of that? The vents I assume just make sure they are clear.

 

[achris]

Re: Fuel pump problem?

Your pump sounds fine. The reason it's dropping at WOT is because the needles in the carb are open to allow fuel in. With will reduce the observed pressure. Remember, pressure is flow that comes up against resistance. If you reduce the resistance (open the needles) with the same flow, the pressure will be lower.

Chris....

 

[gwhjr98]

Re: Fuel pump problem?

Ok.. checked all of the above other than running with an external source which I will try to setup. With a holly 4150 carb.. I assume 3 PSI is not enough to keep it happy. If there are no problems with the pump and the gas tank.. what else can I check?

THanks