Fuel Pick up tube problem

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kjoverbeck
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Fuel Pick up tube problem

Postby kjoverbeck » Sun Dec 10, 2017 10:51 am

While on a cruise in the Abacos this spring running from West End to Green Turtle Cay, we experienced failure in both port and starboard engines. First the starboard then about 30 seconds later, the port. I checked the filters and the bowls had no water or debris. The elements had less than 30 hours on them. I had topped off the fuel at Old Port Cove and had run for about 12 hours at 16 mph. I guessed we used approximately 70 gallons so we should not be out of fuel. Never less, I proceeded to transfer about 20 gallons from the forward tank. Then,both engines, with a little cranking, started and we proceeded to Green Turtle. There I topped off both tanks taking 72 gallons. What happened? Consensus was that it was a problem with the pickup tubes but it seems strange that both tubes would develop leaks at the same place and time. It was a mystery. While at Stuart Yachts, I had them remove the tubes to see if they could find the problem. They appeared ok but both fit loosely in to the fittings. New tubes were put in and sealed. The only thing we can think of is that as the fuel level lowered, it took more suction to pick up the fuel eventually sucking air through the loose fittings. We won’t know until I run the fuel down again. I am not looking forward to that trial. If anyone has any other suggestions, please respond.

Kent Overbeck
2005 PDQ 34, Rising Tide

James Power
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Re: Fuel Pick up tube problem

Postby James Power » Sun Dec 10, 2017 1:01 pm

Hi Kent,

Check the pick up tubes and see if there is a screen at the bottom. At the factory the fuel tank manufacturer supplied pick up tubes with stainless steel screens at the bottom of the tubes. We found that during the flotillas the engines would die due to fuel starvation. After pulling the tubes I found the screens clogged with metal debris from the making of the tanks. Removal of the screens prevented the clogging and any debris that may possibly make its way up the tube will be caught by the Racor filters. A tank scrubbing is also recommended.
On a side note, when reinstalling the aluminum pick up elbow fitting on top of the tank, use some anti seize to prevent galling of the threads.

Hope this helps
James

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Re: Fuel Pick up tube problem

Postby kjoverbeck » Sun Dec 10, 2017 3:16 pm

Thanks James but there were no screens, no debris, the tank had been cleaned, filters ok. All worked fine after I transferred the fuel. The only thing noticed was the loose fit of the tubes. ????

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Re: Fuel Pick up tube problem

Postby James Power » Sun Dec 10, 2017 4:16 pm

Interesting... Could be the loose pick up tube fit, but funny it affected both engines at relatively the same time. Is the tank vent line clear? Do you have vacuum gauges on the filters, and if so what were they showing?

James

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Re: Fuel Pick up tube problem

Postby deising » Sun Dec 10, 2017 4:23 pm

I was trying to figure out what could affect both engine fuel lines at the same time and the vent is definitely all I could come up with. Thanks, James, for being there for us. Good luck, Kent.
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Re: Fuel Pick up tube problem

Postby kjoverbeck » Sun Dec 10, 2017 8:22 pm

Vacuum gauges not showing any restriction. Will check the vent line.

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Re: Fuel Pick up tube problem

Postby duetto » Mon Dec 11, 2017 10:35 am

hi kent,

upon further review...could it be a stuck check valve in the fuel overflow preventer in the vent line?
john & diane cummings
duetto mv34 #23

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Re: Fuel Pick up tube problem

Postby deising » Mon Dec 11, 2017 11:23 am

James would know more than I would, but if the check valve is stuck closed, that would seem to be a good reason for the problem you had.
Duane Ising
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2006 PDQ MV 34 - hull 91, 75HP, 3-blade

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Re: Fuel Pick up tube problem

Postby kjoverbeck » Mon Dec 11, 2017 3:57 pm

To me, it seems that if the check valve was stuck, adding 15-20 gallons of fuel would not have solved the problem.

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Re: Fuel Pick up tube problem

Postby deising » Mon Dec 11, 2017 5:12 pm

Well, in order to pump (transfer) that much fuel into the aft tank, you would eliminate much of the partial vacuum in that tank. Plus, if the vent was allowing air in only very slowly, maybe that bit of time lapse allowed the pressure to come back close to atmospheric.

The reason, to me, that the vent is still a suspect is the fact that both engines lost their fuel flow about the same time.
Duane Ising
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2006 PDQ MV 34 - hull 91, 75HP, 3-blade

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Re: Fuel Pick up tube problem

Postby kjoverbeck » Mon Dec 11, 2017 7:15 pm

James, the gauge tell tale needles on both filters were in the very safe area.

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Re: Fuel Pick up tube problem

Postby James Power » Tue Dec 12, 2017 12:12 pm

A couple of thoughts;

Were there any panel alarms going off when the engines shut down?

Was the on engine Yanmar secondary fuel filter changed?

What length are the new pick up tubes? Is it possible that they sucked air due to their length and vessel trim?

No ropes caught in the props?

James

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Re: Fuel Pick up tube problem

Postby kjoverbeck » Tue Dec 12, 2017 4:33 pm

James
No panel alarms
secondarys both changed
The length was my first suspicion. Stuart Yachts say that not the case.
No ropes.
Remember, all was well after I transferred fuel.
Thanks for your efforts.

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Re: Fuel Pick up tube problem

Postby James Power » Tue Dec 12, 2017 8:24 pm

Still sounds like a fuel delivery issue. If the venting was and is clear, and the drag needle on the Racor gauges was good, it points to running out of fuel. What were the fuel tank gauges reading? Anyone else have any ideas?

James

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Re: Fuel Pick up tube problem

Postby sailkane » Wed Dec 13, 2017 9:32 am

I agree with James, it sounds like it ran out of fuel. You should start by recalibrating the fuel gauge.Use the stick method and do full ,1/2 and 1/4.
Even with fuel in the tank boat trim could have all the fuel in the back of the tank.


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