Fuel pressure loss at high rpm
05-03-2018, 02:17 PM
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Fuel pressure loss at high rpm
Looking for some help tracking down a fuel pressure issue. Port & star both idle at 7lbs. At around 3800, port begins to fall off and sometimes dumps right off to 1 above 4500. I get out of it at that point so I’m unsure if I’d lose it completely above 5. Occasionally if I walk it up really slowly, pressure will hold. Things I’ve already tried
-swapped upper&lower pump(both new 2x)
-new fuel lines from tank to carb
-inspected tank, no issues or anti siphon
-swapped senders& gauges from other engine(same result)
-ran fuel line directly into 5gal can to eliminate a tank problem
-lobe seems fine in water pump. Changed oil
-bypassed water separator
i did run it in a hose once while looking in the tank. The only odd thing a noticed was that when throttled back to idle quickly, an air bubble spit out of the pick up tube. I have no idea what would cause air introduction since I’ve replaced every line.
-swapped upper&lower pump(both new 2x)
-new fuel lines from tank to carb
-inspected tank, no issues or anti siphon
-swapped senders& gauges from other engine(same result)
-ran fuel line directly into 5gal can to eliminate a tank problem
-lobe seems fine in water pump. Changed oil
-bypassed water separator
i did run it in a hose once while looking in the tank. The only odd thing a noticed was that when throttled back to idle quickly, an air bubble spit out of the pick up tube. I have no idea what would cause air introduction since I’ve replaced every line.
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