Some strange reason both motors use same pick up ? If so, $50 there is a hole in the pickup.

Hmm, thats a good point. Same pick up? I know there are two separate lines off the fuel tank. One to each engine. Today wasn't even that hot, ran great for hours of fun, some anchoring, etc. Was end of day, like sunset, when she flopped on me.

Can't see vapor lock this time. And, to lose fuel pressure at same clip, both engines. There was again a distinct hollow metal ping when this happened, like a loud fuse popping or something...It's definitely a common issue, im now thinking commom/shared electrical issue somewhere way upstream..

of note, since the fuel filter changes, I ran her hardly for 20min or so, varying speeds, turned off, back on etc. All was good, so felt more confident to go out today, then this...


Would this pick up be somewhere in the tank?

Tank flexing and making noise ? I’ve heard it several times in cars from bad vents. Loud ! This (bad vent), causes loss of fuel psi too.

edit in: the car tanks where steel. Not sure what aluminum tank would sound like, if it would even make one ? Dunno.

You sure the noise isn’t quick intake backfire ? That would happen when fuel pump psi gets low enough to lean sneeze.

Open the gas cap to see if the vent is plugged .

Quick intake backfire may be a descriptor. Not sure. As for gas cap, no vacuum noise when removed.

As the boat has sat this evening, fuel psi on Smartcraft, ignition on only, both engines have dropped fuel psi. Now sitting around 6psi. 4 hrs ago,, both were around 11. When all was good earlier, both were at that 40psi within specs...

fuel pressure regulators

i would run the boat without gas cap for a day ! This way you can rule out vent problem if that is the case

Run it for a while, stop and open gas cap and listen if air gets sucked in

That’s with engine off. Fuel psi is slowly leaking past fuel pump check ball. Thisvwill not cause psi to drop while running.

Key on, engine off willl only turn fuel pumps on for say 5 seconds.

Ian, did you see my thread "Adventures in 525 fuel filter replacement?" You were right. It was a b*itch but you had me prepared.