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  #11  
Old 07-06-2011, 05:00 AM
N223JH N223JH is offline
 
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Location: Boerne, TX
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IIRC there are four weep holes in the pump. Because car gas doesn't leave convenient blue stains like avgas, you may need to use a swab with some kind of solvent to pick up evidence of leakage. These pumps have been known to leak along the two crimped seams also. Because Rotax policy on warranty replacement requires statement of leakage, you really want to find something.

I think I am the only one who ordered just the replacement pump. I didn't want to roll the dice on $500 and I had put special insulation on my fuel hose already. It was not difficult to carefully Dremel off the clamps on the pump. Somebody on your airport likely has the stainless clamps and tool for the factory-like re-installation of hoses.

The service center will send you the forms. Of course the English instructions are in fine print, so be careful to fill it out correctly. I was told by Lockwood that they would likely make good on my claim because, "Rotax knows there is something wrong with those fuel pumps."

Here's hoping the new, improved models are more reliable.

Jim
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  #12  
Old 07-06-2011, 08:16 AM
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MartySantic MartySantic is offline
 
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Just a thought......

If ordering the fuel pump with hoses, I would ensure Van's did not somehow SPECIAL order the engine with hose lengths designed for the RV-12.

Anyone know??
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  #13  
Old 07-06-2011, 08:19 AM
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MartySantic MartySantic is offline
 
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Quote:
Originally Posted by N223JH View Post
It was not difficult to carefully Dremel off the clamps on the pump. Somebody on your airport likely has the stainless clamps and tool for the factory-like re-installation of hoses.
There is a nice video on the EAA website showing the removal, installation and the tools required to remove and/or install these clamps on the hoses and then another for the firesleeve.
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Davenport, IA
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  #14  
Old 07-06-2011, 03:49 PM
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Jetguy Jetguy is offline
 
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Location: Texas, Fort Worth
Posts: 1,233
Default Yes the pump with the hoses will work!

John P,
The pump with the hoses will work in the RV12. Ask me how I know! Just because the pump is not leaking doesn't mean that its still not going bad. Ask Jim how he knows. All you have to do on the Paper work for the return is State, "After testing the pump per the Rotax Maintenance manual it was found to lose pressure intermittently, possible leak in pump. Replaced with new pump part #893114". This is the part number for the new pump with the hoses attached per the Rotax-owner.com web site. Go back and read this thread:
http://www.vansairforce.com/communit...ight=fuel+pump

See my post Dated: 05-08-2011, 09:56 PM The basic symptom of pump failure is first a leak or no leak (Ask Jim how he knows)with High fuel flow in to the red followed by an Alarm tone on the Dynon. Next a decrease in fuel pressure which occurs at a slower rate then the fuel flow symptom. Fuel Pressure may not go to zero just down into the yellow with no alarm. As I have stated before this is a very insidious problem. You may have had a Hiccup like Marty had or with more flying over a period of time if the pump is going bad the symptoms will become more pronounced. I don't think the engine will stop running altogether it will just start to lose some power. So you might want to try some more flying till you see the symptoms. Good luck and let us know how it works out.

This maybe the link to the EAA video that Marty was talking about I think.
http://bcove.me/3mztmj1l
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RV12 N1212K
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RV14 Wing, arrived and building at Rdog's new Hanger at 16X
S/N 140014

Last edited by Jetguy : 07-06-2011 at 04:19 PM.
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  #15  
Old 07-06-2011, 04:24 PM
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MartySantic MartySantic is offline
 
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Quote:
Originally Posted by Jetguy View Post
This maybe the link to the EAA video that Marty was talking about I think.
http://bcove.me/3mztmj1l
Yep, that is one of the videos. The other video is here.....

http://www.eaavideo.org/video.aspx?v=44938120001
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  #16  
Old 07-07-2011, 11:20 AM
BigJohn BigJohn is offline
 
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Very busy last couple of days but I did get to the hangar yesterday long enough to pull the cowl. The fuel pump is bone dry with no leakage stains. The electric pump produces about 1.8 PSI which increases somewhat when I pull the engine through by hand. I still have more questions than answers. Hopefully things slow down a bit tomorrow and I will have time to ponder my next move.

Thanks to all who have responded with information and thoughts.

John
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  #17  
Old 07-08-2011, 07:24 AM
BigJohn BigJohn is offline
 
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Thanks to all who have responded. I need all the help I can get - I am NOT a mechanic, and yet I now feel I have been thrust into that realm by this issue, which with my limited expertise, seems quite complex. If you will humor me, I will try to organize my current questions, and reply to some of the above.

To David Paule - correct, no leak.

To Jim N223JH - Fuel pressure was steady.

To Peter K. - I wish I understood better the internals of the pump. But PRESSURE does not change. Indication of FLOW is what changes.

To Joe Gores - I like your logic, however, there is no discrenable rise in fuel PRESSURE that I can see on the data. How can the FLOW increase if the PRESSURE remains constant?

To Marty - Thanks for the data analysis. I will call you to dicuss when I have some time. I need your help to inperpret the graphs.

To RDOG - I believe you, but where would the pump be sucking air FROM?

To John Bender - How in h*ll can those two hoses be worth $395?! That is blowing my mind! And as I understand it, I can only get warrantee replacement if the pump is leaking.

To N223JH (again) - Jim , I only find two weep holes in the pump. There are no stains on those or around the crimp. (Was running 100LL during incident, so should show blue stain.) I will look at it again to try and find the other two holes. My inclination is to order just the pump with the barbed fittings, as you did, since I think there is a high risk of not getting the warrantee payment..

To Marty (again) - I downloaded the pertinent pages of Rotax SI-912-020 R5, and that document has nice pictures of the new pump, hoses, etc., but no hose length specified. That seems odd. Are we just to assume the lengths are the same as the old ones? Now here's a new twist. There is a statement in the SI that if an auxiliary electric fuel pump is used there must be a check valve installed in parallel. See 73-00-00 page 7 of 10. Does this mean we should have had this installed all along? Or, does it mean it is specific to the new pump and we need to order and figure out how to plumb in the check valve when we install the new pump?

To Jetguy - Thanks for the advice on getting the part paid for under the warrantee. Being a bit of a skeptic, I have to wonder has anyone actully been paid yet using this phraseolgy? Also, see comment above re: the paralell check valve. I'm not sure how to get a definitive answer on that.

I have reached the point where I definitely want to replace the pump, but I'm sure not clear on the details. Anyone, please add more information as you get it.

John
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  #18  
Old 07-08-2011, 07:33 AM
Peterk Peterk is offline
 
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Location: Texas
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John,

I bought the new pump (only) from Leading Edge yesterday. Will let you know what I think following install etc. I'm way past warranty hours and time frame but I did have a bad ignition module ($992) early on and they took care of that. Good luck.

Pete
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  #19  
Old 07-08-2011, 08:39 AM
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Jetguy Jetguy is offline
 
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Default Pump Refund

John,
I bought a new pump with the hoses from LEAF under warranty, Filled out the paper work and returned bad pump, mine leaked, got a full refund within 30 days, no problems. Are you still under warranty? Why dont you think they wouldn't refund the pump under my phraseology? Have you watched the video on Rotax-owner.com about testing the pump? Call LEAF if you want and ask for Linda and tell her the Phraseology exactly as I printed it and nothing else and see what she says. If you cant duplicate the problem again then just keep flying till it occurs again. If you have constant fuel pressure then you pump maybe working fine and you Fuel flow cube could be going bad or has a loose connection. Try resetting your wires at the flow sensor. If you don't want to do that then just by a new pump with out the hoses and reuse your old ones. The pump with out the hoses is around $160.00. When the new pump comes in take it to your local A&P and have him put the old hoses on the new pump for a small fee. Some times something occurs and its just a hiccup in the system, then it goes away, so long as all your other engine indications were fine and the engine continues to run smoothly just fly some more. Good Luck
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RV12 N1212K
Flying Since June 2010
1020 Hours as of 9/30/2017
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RV14 Wing, arrived and building at Rdog's new Hanger at 16X
S/N 140014

Last edited by Jetguy : 07-08-2011 at 08:44 AM.
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  #20  
Old 07-08-2011, 08:44 AM
Mich48041 Mich48041 is offline
 
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Location: Riley TWP MI
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Default How can the FLOW increase

Quote:
How can the FLOW increase if the PRESSURE remains constant?
According to the laws of physics, the pressure must change when the flow rate changes. Chances are that the pressure is changing but the sensor is not a precision transducer capable of indicating small changes. Now the question is, does the fuel pressure go up or go down when the flow goes up? If the pressure goes up, that means that the pump is putting out more. After thinking about it, that is unlikely. The other guys are probably right that the engine driven pump is leaking air. Either that or the fuel is vaporizing and forming little bubbles. A small amount of fuel vapor or air mixed with fuel will allow the fuel to flow easier with less friction. And so the flow goes up.
Supposing that a person is reluctant to replace the pump due to expense and time and trouble. How can the fuel pump be tested? Here is an idea that I have not tried: Pull up the red knob to close the fuel supply line. Hold bulkhead fitting with backup wrench and disconnect the fuel return line at the firewall shelf and apply about 6psi air pressure to it. Assuming the carburetor float valves stay closed, there should be no leaks. Observe the vent holes on the fuel pump for any sign of leakage.
Air can leak though a hole that is too small for liquid to leak through. When the fuel pump diaphragm first starts to fail, it will have a very small crack. Theoretically, it is possible for air to leak into the pump on the intake stroke without fuel leaking out on the compression stroke.
If the high fuel flow problem goes away after replacing the engine driven pump, then you will know that the pump was defective.
Bottom line is that I agree with the other to replace the pump.
Joe Gores
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