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  #1  
Old 02-10-2021, 03:59 PM
alcladrv alcladrv is offline
 
Join Date: Oct 2006
Location: Southeast
Posts: 614
Default Facet boost pump lifespan

An avgas odor was pretty noticeable the last couple of mornings as I slid the canopy back on my -7A with a carbureted O-360.. Today, I investigated so out came the front carpet and off came the tunnel cover to expose the fuel selector valve and the Facet boost pump.

The inlets to the fuel valve were both good and tight, but the outlet port could be tightened about 1/4 turn. I thought that would take care of the odor.

But, while I had everything opened up, I used the wrenches on the boost pump. The outlet was good and tight. But the inlet on the bottom could be tightened close to a full turn and it didn't seem to bottom out. The problem was that the more I tightened the inlet, the avgas odor became more apparent. I didn't want to overdo it, so I thought I'd let it sit overnight with a white paper towel beneath it to see if avgas leaked out..

The questions are: The pump is 16 years old with typical usage during 1600 hrs. Mostly, I've run avgas, but have used no ethanol 91UL on occasion. Do these pumps have a typical lifespan? Does mogas use shorten the lifespan? If I continue to tighten the inlet until it noticeably bottoms out without getting it overly tight, will I harm the pump or worse split the fuel tubing and create a very noticeable leak?

Until now, the fuel system has worked normally without any issues.

Thanks!

Last edited by alcladrv : 02-10-2021 at 04:02 PM.
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  #2  
Old 02-11-2021, 06:21 AM
fixnflyguy fixnflyguy is online now
 
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Location: Winston-Salem, N.C.
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Default Not sure, but I have two on my plane

So, I will watch this post closely, as I depend on the very reliable little square pumps more than most. I run two of them on my carbureted O320H2AD, one as "full time" fuel pump, the other as boost/backup pump. I do not run a mechanical pump because the H2AD mount boss would have caused an unsightly (to me) bump in my upper cowl. I have been running these pumps for 11 years and about 400 hrs. with no issues. Curious to see others observations.
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  #3  
Old 02-11-2021, 08:38 AM
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DeeCee 57 DeeCee 57 is offline
 
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Default

well, my ship sports 1 engine driven + 2 facet pumps, all of em 2005 vintage. One of the facet is used for take-off, then switched off in the cruise, the other one is then switched on for landing.

The mechanical pump still delivers a reliable 4psi, the facets up to 6.

Re your fuel leak, I would not tighten anything anymore. Better make sure all mating surfaces and the tubing flared ends are good. Iíve never seen a properly tightened AN fitting work itself loose...yet.
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  #4  
Old 02-11-2021, 09:23 AM
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Sam Buchanan Sam Buchanan is offline
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Default

Quote:
Originally Posted by alcladrv View Post

But, while I had everything opened up, I used the wrenches on the boost pump. The outlet was good and tight. But the inlet on the bottom could be tightened close to a full turn and it didn't seem to bottom out. The problem was that the more I tightened the inlet, the avgas odor became more apparent. I didn't want to overdo it, so I thought I'd let it sit overnight with a white paper towel beneath it to see if avgas leaked out..

Thanks!
The flare may be cracked, if so you won't be able to make it stop leaking until you replace that line.

In regard to your service question, my 1999 Facet pump is still working. I've wondered if it would be prudent to replace it but I'm more concerned about "infant mortality" of a new (off-shore?) pump.
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  #5  
Old 02-11-2021, 01:42 PM
abwaldal@gmail.com abwaldal@gmail.com is offline
 
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My 2001 facet was still doing it's job after 20 years of service. Removed to install fuel injection requiring higher fuel pressure
Art
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  #6  
Old 02-11-2021, 02:45 PM
YellowJacket RV9 YellowJacket RV9 is offline
 
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Location: Clearwater, FL KCLW
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Default

[quote=DeeCee 57;1502398]well, my ship sports 1 engine driven + 2 facet pumps, all of em 2005 vintage. One of the facet is used for take-off, then switched off in the cruise, the other one is then switched on for landing.
/QUOTE]

I have to ask, what is the reasoning behind the dual boost pumps?

Chris
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  #7  
Old 02-11-2021, 06:54 PM
alcladrv alcladrv is offline
 
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Default

Thanks for all of your responses.

I just got it an order from Aircraft Spruce. Are there any other sources of the 3/8" fuel tubing besides the usual aviation suppliers?
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  #8  
Old 02-12-2021, 12:44 AM
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DeeCee 57 DeeCee 57 is offline
 
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Chris, talked some about fuel systems in this thread https://vansairforce.net/community/s...d.php?t=191331

The original builder designed the fuel system with dual el pumps and a return line for the use of Mogas and to lessen the chance of vapor lock. Dual facet for redundancy. Despite all of this I’ve had vapor locks on ground and in flight a couple of times... my bad each time since I had either el pump off
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  #9  
Old 02-14-2021, 04:58 PM
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avrojockey avrojockey is offline
 
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Default

The little square facet pumps should be pretty reliable...more than the mechanical one. They're solid state, and the only moving part is the piston...see video...

https://www.youtube.com/watch?v=Dtf66p8M11g
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  #10  
Old 02-14-2021, 05:23 PM
NYTOM NYTOM is offline
 
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Thumbs up New fuel line in order.

I agree with Sam on this one. The tubing is soft aluminum and the fittings are steel. If it still leaks after tightening that much, something is definitely wrong.
Also there is a chance the flare wasnít made correctly to begin with and over time has failed. Replacing the line with proper flares will probably solve your problem but use proper torque when tightening. They can crack a lot easier when the flare has been over tightened.
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