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Backup fuel pump?
Posted: Wed Jun 04, 2008 2:30 pm
by coen
Need information on how to add a backup electrical fuel pump to the existing fuel supply on a microlight(582/503) .Contemplating an additional fuel fiter in a parralel configuration. I need some advice on wether it is viable proposition. Any sugestions will be appreciated.
Many thanks Coen.
Re: Backup fuel pump?
Posted: Wed Jun 04, 2008 2:42 pm
by Morph
Discussed in great detail here
viewtopic.php?f=13&t=309
In short, install it in series, not parallel. The pump does not have a one way valve. If installed in parallel then you could get fuel flowing back through the spare pump, reducing fuel pressure and resulting in problems
Re: Backup fuel pump?
Posted: Wed Jun 04, 2008 5:53 pm
by Wargames
Morph wrote:Discussed in great detail here
viewtopic.php?f=13&t=309
In short, install it in series, not parallel. The pump does not have a one way valve. If installed in parallel then you could get fuel flowing back through the spare pump, reducing fuel pressure and resulting in problems
What is the appr. price of the facet pump??
Another advantige of a pump is that when your system is presurised, you can see leaks, that would other have the ability to suck air into system.
Regards,
Re: Backup fuel pump?
Posted: Thu Jun 05, 2008 9:18 am
by Morph
I believe they are around R400 now. Definately worth the investment, believe me.
Re: Backup fuel pump?
Posted: Sat Jun 07, 2008 10:52 am
by cjkrit
I do not want to cause any confusion but it is stated on
www.ultralightnews.com that such a pump be in parallel. Quote: If an electric pump is to be installed run the pump in a parallel configuration with the fuel pickup prior to the vacuum pump and inserted back into the system, after the pump. Make sure that the electric pump you select does not put out more pressure than is recommended or you could cause your carbs to fail.
I have read that in serie if the backup pump is not operated it could cause some resistance to the fuel passing through it. Is this only used for take-off and landings or is it left on all the time? Purchased one this morning and this one allows no backflow of fuel- some type one-way valve. If switched off it wil not allow flow in opposite direction.
We need more clarity on this. Comments?
Christo
Re: Backup fuel pump?
Posted: Sat Jun 07, 2008 12:05 pm
by Arnulf
cjkrit wrote:I do not want to cause any confusion but it is stated on
http://www.ultralightnews.com that such a pump be in parallel. Quote: If an electric pump is to be installed run the pump in a parallel configuration with the fuel pickup prior to the vacuum pump and inserted back into the system, after the pump. Make sure that the electric pump you select does not put out more pressure than is recommended or you could cause your carbs to fail.
I have read that in serie if the backup pump is not operated it could cause some resistance to the fuel passing through it. Is this only used for take-off and landings or is it left on all the time?
Purchased one this morning and this one allows no backflow of fuel- some type one-way valve. If switched off it wil not allow flow in opposite direction. We need more clarity on this. Comments?
Christo
Hi Christo,
which pump did you buy?
I would also prefer a parallel installation, however does your engine driven pump have a non return valve? Other wise you might have a problem that the electrical pump does not deliver enough fuel to your carbs. Just wondering
Regards,
Arnulf
Re: Backup fuel pump?
Posted: Sat Jun 07, 2008 4:44 pm
by cjkrit
I listen to what you say- The pump is a no-name brand- this one has a non-return valve. Seems like the Facet pump is the one to go for. No valves will cause least resistance to flow if pump is switched off. The parallel installation seems to complicate matters. I do not have so much knowledge of the Mikuni pump on my 582, whether non-return or not, I really don't know.
The postings on this forum tell of guys who has the serial installation for long time, and it works well.
Backup fuel pump?
Posted: Sun Jun 08, 2008 6:38 am
by John Young
Arnulf wrote:However does your engine driven pump have a non return valve? Other wise you might have a problem that the electrical pump does not deliver enough fuel to your carbs. Just wondering.
Hi,
On the 582, I suspect that Christo has the standard diaphragm pump - meaning that one or both butterflies will always be open to allow fuel through.
The in series installation is fine using the tank – facet – filter – diaphragm pump configuration.
A parallel installation certainly requires a lot of extra plumbing. I have a parallel configuration on my trike, meaning two pick-up lines, two filters, two ‘T’ pieces allowing the carburettors to be independently fed by either of the facet or mechanical pump systems.
cjkrit wrote:I listen to what you say- The pump is a no-name brand- this one has a non-return valve. Seems like the Facet pump is the one to go for.
Hi Christo,
It is very important to have a facet pump that does not deliver more than 3 psi. Some facet pumps are capable of delivering a much higher pressure which will cause damage to the needle and seat (very expensive and dangerous).
Here is another link - unfortunately the punctuation got a bit messed up when Microlighters changed over to this software.
viewtopic.php?t=3840&postdays=0&postorder=asc&start=0
Regards
John
Re: Backup fuel pump?
Posted: Sun Jun 08, 2008 8:35 am
by Duck Rogers
John Young wrote:A parallel installation certainly requires a lot of extra plumbing. I have a parallel configuration on my trike, meaning two pick-up lines, two filters, two ‘T’ pieces allowing the carburettors to be independently fed by either of the facet or mechanical pump systems.

And that's the way I believe it should be.
Re: Backup fuel pump?
Posted: Sun Jun 08, 2008 10:31 am
by Wargames
Duck Rogers wrote:John Young wrote:A parallel installation certainly requires a lot of extra plumbing. I have a parallel configuration on my trike, meaning two pick-up lines, two filters, two ‘T’ pieces allowing the carburettors to be independently fed by either of the facet or mechanical pump systems.

And that's the way I believe it should be.
Hi oom Duckie,
Care to share your views as to why you would suggest a paralel instalation. I did a serial instalation this weekend. My instalation is Fuel tank -> filter -> facet -> fuel flow sensor -> machnical pump -> carbs. I am thinking of instaling another filter before fuel flow sensor, but would like to know whether serial is ok.
Regards,
Re: Backup fuel pump?
Posted: Sun Jun 08, 2008 11:29 am
by cjkrit
Check out the following site:
http://www.challengers101.com/FuelSys.html.
Lot of detail and discussion. According to what they say both the Facet and Mikuni pump have built-in valves to prevent backflow. If so, this could make even a parallel installation quite simple.
Re: Backup fuel pump?
Posted: Sun Jun 08, 2008 2:46 pm
by Duck Rogers
Wargames wrote:Care to share your views as to why you would suggest a paralel instalation
Wargames.......
cjkrit has answered the question for me
Very comprehensive article to which I have personally referred to many times.
Re: Backup fuel pump?
Posted: Sun Jun 08, 2008 4:35 pm
by coen
To all replies on the backup fuel pump. All replies and info much appreciated. Midas sparepart number on high and low pressure is the same. The only differance be-ing that the low pressure has a 42 number on the box and the high pressure has a 44 digit on the end of the number on the box . The facet pump can be blown through from both sides, so I placed it in series and it works like a charm. After having not been started for two weeks I pressurized the system and the 582 fired on the first turn
Thanks again
Coen
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Re: Backup fuel pump?
Posted: Sun Jun 08, 2008 7:40 pm
by John Boucher
So.... you used the Facet low-pressure fuel pump?
What is the Midas part number of the pump you used please?
I suppose one would use the high pressure for fuel injected systems?
Re: Backup fuel pump?
Posted: Mon Jun 09, 2008 8:18 am
by John Boucher
Just bought a FACET pump thought you guys may want the fitting destructions
First Specs:
on the box number is 40105 alternate number is 40242.
on the pump number is EFP-3 other side 50104 and 051805.
12volts and 1.5-4PSI.
Answered my own question.... from another thread!