Help Identifying Cause of Low Fuel Pressure

[dshack]

I could use some help with a fuel issue I'm having in my 2001 SAN (Here is the background on the boat). I took it out for the first time and the boat struggled to get over 1800 RPM and can't get on plane. It sounds decent in idle and revs up out of gear. It just doesn't have hardly any power under load, runs rough, etc. I immediately replaced the rotor / cap / wires / plugs as this hadn't been done in a while.

Before taking it back out to the lake to test to see if the ignition tune-up resolved the issue, I put a fuel pressure gauge on the fuel rail and ran the boat off a hose. To my surprise, I'm getting 10 PSI off the schrader valve on the fuel rail and the HP pump. I talked with the prior owner and he has a video of 40 PSI when running the engine out of the boat. He also just replaced the LP and HP pumps, filter, injectors, etc. I have absolutely no reason not to trust him, he's been very helpful giving me more ideas to try and even offered to send me a new pump.

Here's what I've done so far (w/ references to Service Manual):

• 3H-1: Visually inspected everything from tank to injectors and can't see any obvious issues to my somewhat untrained eye
• 3H-2: Fuel pressure is only 10 PSI when idling / under throttle. Does not budge when giving throttle.
• 3H-3: Ran both pumps for 30 seconds using STO jumper and the pressure goes to ~8 PSI. It immediately drops to 0 PSI when pulling ground. Per the service manual, it should hold within 3 PSI for 3 minutes, but this might be only in the case you are getting ~40 PSI? I'm not sure on this one.
• 3H-11: Ran pumps by grounding the STO connector with key on, engine off and I can hear / feel both pumps running
• 3H-12: Checked voltage at pump, power is getting to both HP and LP pumps (12.5V)
• 3H-13: Checked fuel pump ground, getting about .3 to .5 ohms so good here.
• 3H-14: Filter has only ~2 hours of runtime.
• Swapped relays, no change
• Pulled fuel hose off anti-siphon valve and inserted end of hose straight into tank (via opening for fuel sensor). Still getting 10 PSI.
• Pulled fuel hose off connection from LP to HP tank and ran pump using STO ground and fuel flowed very well into a bucket (I think I saw somewhere they suggested 1 qt per 15 seconds and that seems about what I got)

Based on the above, it seems like the logical next steps would be to:

• Pull the FCC and inspect the filter and pickup tube (PO just replaced them though)
• Replace the fuel pressure regulator

What else should I try??

THANKS!!

[dshack]

Pretty sure I found the issue! Tube was totally shot. Do I need to order this part online or is it something generic I could find locally?

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