Stalling issue

[Michigan_SAN]

Boat is a 2002 SAN GT40. Had it for 6 years and it’s been great. This summer it’s started having a random stalling issue. It’s just as likely to happen at idle as it is at cruising speed or when pulling a wakeboarder up. At idle the boat just shuts off like somebody pushed the stop button. At speed it will hesitate for a bit but keep running. It’s very intermittent. Boat will run perfectly fine for over an hour one day then die a couple times the next. I’ve already replaced the lanyard kill switch which did not help. I’ve hooked up a fuel gauge and at idle I get about 33 psi. When I raise the throttle it will dip a bit to 30 psi and generally recover to 33-35 psi. It doesn’t get above ~35 psi however. I believe it should go to 40 psi when >2000 RPM. My tach is illegible (crappy Teleflex gauges) but if I’m cruising around at 25-30 mph it still only reads 33-35 psi. I tried pulling the vacuum hose off the fuel pressure regulator ant idle and then the fuel pressure jumps up to 40 psi.

Anybody have any ideas or further troubleshooting steps? My fuel pumps are pretty hard to get to with the V drive configuration so I’d rather not replace them unless I’m fairly certain that’s the problem.

[Baz]

I’m certainly no expert. I was having the same issue same boat/motor but only at idling speed. Changed the fuel filter and problem was solved for us.

[Michigan_SAN]

I’m certainly no expert. I was having the same issue same boat/motor but only at idling speed. Changed the fuel filter and problem was solved for us.

Thank you, this is my leading suspect at the moment. I assume this was the fuel filter inside the FCC?

[Baz]

Yes…….hope it works out for you.

[FMSKI]

~35 PSI is fuel more than enough to keep the engine running. Good flow is required at high output, if the filters are clogged then pressure would drop off starving the engine.
Confirm it isnt fuel, then check or monitor the 12V at coil +ve terminal. That 12V test point is downstream of the Key on +12V, EEC relay contacts, upstream breakers.

[JayG80]

Replace fuel filter as suggested above and while you are at it replace the 2" long hose that suspends the high pressure pump inside the FCC canister. The hose may develop a crack and reduce fuel flow and performance.
https://skidim.com/hose-kit-fcc-h-p-pump/

Another bit of advice is to replace the electrical wiring grommet on the top of the FCC with the FCC Repair Kit. The original epoxy around the harness is aged and allows fuel leaks from the top of the FCC to the engine area.
https://skidim.com/fcc-repair-kit/

From my GT40 notes

[Michigan_SAN]

UPDATE: Decided to crack open the FCC and do the maintenance I’d been putting off. I’d been avoiding doing this because I’d read about how hard the FCC can be to get off and looking at its placement in my boat, it didn’t look like a fun job. Well, thanks to the previous owner who so kindly put petroleum jelly on the O-ring and threads, it was a breeze to get the FCC unscrewed. Replaced the filter, high pressure pump, wire feed-thru, and short rubber fuel line inside. Put it all back together and it’s running again. The idle sounds a little faster/stronger than before, although I hadn’t thought it sounded rough before, it’s just better now. Ran the boat at various speeds for 2 hrs with no stalls yet. Hopefully that was the problem and it’ll continue running strong for the rest of the season. Learned my lesson, I’ll be replacing the fuel filter at least every 2 years now.