[Travis]

Good morning.
I had an enjoyable last season on the boat. No Issues.
It sat in the water all winter 2 months unused, and is now off slip as of last Thursday.
Took a spin yesterday. 5 adults on board. 1/2 fuel. 3/4 water.
Engines laboured to make 3000 rpm. All gauges read normal
After 5 mins, port engine shut down without warning. Left it for 10 mins. started and manoeuvred into slip no problem.
pumping water, fuel bowls clear. Fresh fuel.
Changes made: Added 300lb generator. Painted propellors.
Any ideas on cause?

Travis

[RCKLAW]

This is a long shot: My 1995 454 with fuel injection would not hold rpms and eventually cut out mysteriously - mechanic first thought electrical and then fuel. After trying many fixes - and throwing a ridiculous amount of money at the problem - it turned out to be a defective anti-siphon valve in the fuel tank that prevented fuel from being drawn from the tank.

[reeltimebrad]

Sounds fuel related, how long since filter changes? Are both engines running the same? Painting props probably has some effect but not that much.

[jclark003]

Not uncommon for a plugged fuel vent to exhibit the same symptoms too. Easy check is to run it with fuel cap off (assuming calm seas and no weather) or pull cap right after shutdown and listen for air being pulled back into tank.

[Travis]

I drained the fuel in the filters yesterday. No water. Clean filters.
No load has the engines spooling up.
I will check the vent today.
I was also thinking maybe debris in tank or fuel pickup tube.
Things to check! lowing 25+ knots today. NO TESTING!

[reeltimebrad]

Pull the sending and use a strong flashlight to peer into the tank you may be able to see the pickup tube and possible presence of debris.

[Misdirection]

To eliminate the gas tank & anti siphon valve, can you run off the other tank? Simple to test and doesn't cost anything except your time.

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[efontana]

I'd bet it is one of these things:

1. The fuel pump relays are known failures, when they start to fail, they just quit, restarts sometimes make them close again. Get some spares.
2. The pickup coil at the bottom of the distributor is going.
3. Pickup tube/anti-siphon valve.

[Misdirection]

I had a strange issue last year on my last trip before winterization. Boat would backfire and stall at idle, wouldn't make power past 2000 rpm. The seal on the distributor cap was bad and moisture got under the cap. I replaced the cap and motor and that resolved my issue. Point being check the simple things first.

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[Travis]

I finally was able to get a mechanic to the boat, (I was travelling well, so delay there too) and we found a few things wrong.
Inside the distributors were a little green.
The Port side coil (shutdown engine) was cracked all the way around the top.
We cleaned all of the raw water system out.
Changed all of the salt water hoses.
Will test and report back.