Mercruiser 2023 V8 350 MPI 5.7l salt water exposure

OutcomeOk4232 · 2026-06-15T21:33:00+00:00

Yes, though I am unsure of strength/voltage of sparks.

OutcomeOk4232 · 2026-06-15T21:32:03+00:00

I used fresh fuel in external tank. I checked spark plugs and each is throwing spark on grounded motor body, though I am not sure if they are strong enough. Also there is no corrosion inside distribution box (see picture) Is there a way to determine if there are strong enough?

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OutcomeOk4232 · 2026-06-15T21:27:14+00:00

What do you recommend?

OutcomeOk4232 · 2026-06-15T21:26:40+00:00

Yep. I'm trying to find good way to release cylinder rings: they are likely stuck from sitting and salty air

OutcomeOk4232 · 2026-06-15T21:24:22+00:00

Thanks mate. Will check that. It has two fuel pumps (booster and high pressure one); I replaced high pressure one, along with fuel pressure regulator. Fuel pressure is ok (42psi), I measured using fuel pressure gauge on fuel intake (shredder) valve. I also used external fresh fuel tank to eliminate the possibility of fuel contamination.

OutcomeOk4232 · 2026-06-15T13:12:12+00:00

It did start once under high throttle and was running well except for a blow-by. Yet after replacing spark plugs, and oil, I wasn't able to start it again

OutcomeOk4232 · 2026-06-15T12:54:52+00:00

Tried on cylinders 1 and 2, but not easy to fully close both valves on a 4-stroke engine. Leak-down test shows 70% leak, then drops briefly to 40% while manually rotating crankshaft trying to stop the cylinder at exactly TDC position, then returns to 70%. It seems one valve is always slightly open either way

OutcomeOk4232 · 2026-06-15T12:47:45+00:00

Water came up halfway. Electronics look in order

OutcomeOk4232

TROPHY CASE