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  #11  
Old 06-29-2011, 12:11 PM
DanBaier's Avatar
DanBaier DanBaier is offline
 
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Location: Rochester NY
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Default

Additionally, you could also check to see that there are no chances of a leak where air could enter the line (ie., a drain valve or B nut). For example, the scenario you describe has occured with a not completely seated gascolator drain valve on a piper cherokee. (Pitch up a little, and it sucks air - interrupts fuel flow - engine quits. Pitch back to level and the engine lights off again.)
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  #12  
Old 06-29-2011, 12:52 PM
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Ron Lee Ron Lee is offline
 
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I have possibly the identical fuel setup as you yet I have NEVER had the engine stop upon take-off. Never. Not once. Fuel pressure does drop at times but who cares?

I biased my RMI engine monitor fuel pressure just to end the annoying alarms when the INDICATED pressure drop to zero (Tenths not possible).

So the only suggestion I can add is perhaps not let the fuel pressure concern you compared to a possible fuel delivery issue as already discussed.
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  #13  
Old 06-29-2011, 01:07 PM
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Sam Buchanan Sam Buchanan is offline
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Location: North Alabama
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Default worn carb float?

Another item to check is to see if the carb float pivot has worn to the point where it would allow the float to touch the sides of the bowl. This can make the float hang and prevent the needle valve from working properly. Have someone knowledgeable drop the carb bowl and check for any shiny wear spots on the float.

I had a similar problem with fluctuating fuel pressure that could be "cured" with the boost pump. I replaced the fuel pump and installed a reman carb and fuel pressure has been solid since. I think the pump was the issue in my case but a sticking float can also cause problems.
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  #14  
Old 06-29-2011, 04:24 PM
drycreekrv drycreekrv is offline
 
Join Date: Sep 2008
Location: Houston, Texas
Posts: 10
Default Add me to this list

To All,

Thanx for the discussion about this matter. I am having the same
exact trouble. RV6 w/0360 ie: and using the Facet Pump the revive my engine with I exprerience this trouble - it's quite alarming.
(**** - I hate crashing !!!!)

I've check the ENTIRE fuel system 2 different times without a satisfying
result.

Okay - this time -- I'm buying ANOTHER Engine Driven Fuel Pump --
and -- sending in my carburetor for repair/verification of the Float,
Re-inspecting all fuel and vent lines, Gascolator, checking for leaks
and so on.

If anyone has any more ideas, please reply to the Website before
someone becomes a tragedy.
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  #15  
Old 06-29-2011, 04:33 PM
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Ron Lee Ron Lee is offline
 
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Had the engine ever stopped running during take-off PRIOR to installing the new Facet fuel pump? If the engine had never quit before...and after installing a new fuel system component the engine did quit...look to that installation for a problem.

A 0.5 psi fuel pressure may still have the engine running all day.

Last edited by Ron Lee : 06-29-2011 at 07:19 PM.
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  #16  
Old 06-29-2011, 04:57 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
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Default fuel system

Get rid of the gascolator and replace it with all metal race car filter behind the firewall. Install a shroud with ram air on the engine driven pump. Try to avoid 90 degree fittings in fuel lines. All lines forward of firewall should be highest quality hoses with firesleeve. Try to avoid vertical curves in hoses. In other words the line from firewall to pump should not run uphill and then downhill or vice versa, all excess hose should be oriented horizontally.
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  #17  
Old 06-29-2011, 07:15 PM
foka4 foka4 is offline
 
Join Date: Jul 2009
Location: Ankeny, IA
Posts: 210
Default Another thing to try

I recently started flying my RV-4, which has a tight cowl and a very tight engine compartment. I experienced "vapor lock" problems on my first few flights, but the problem was most evident on rollout after landing. I had to tow the aircraft back to the hangar after the first few flights, because the engine died shortly after landing and wouldnt restart until the engine cooled off.

For me, the fix was a piece of fire sleeve over a short section of stainless steel tubing I ran from the firewall to the gascolator. Lesson learned: insulate ALL of your FWF fuel lines from heat.

As a precaution, I now run the Facet pump all the time. If it ever wears out, I'll buy another one. I'm a glider pilot, so landing dead stick isn't at the top of my list of fears, but a Facet pump is cheaper than a broken wheel fairing from a well executed off-field landing, so it's cheap insurance in my book.
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  #18  
Old 06-29-2011, 08:00 PM
dougknight dougknight is offline
 
Join Date: Jan 2006
Posts: 106
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Thanks guy's
Lots of good info we hadn't thought of for us to look at.

Geico266
Sorry if I was misleading but it is occuring most often when cold not hot.
" Make sure the facet pump is in good working order." I have wondered about the facet pump if it could somehow cause a restrictsion when it is off? Any body ever found this to be a problem?

sig600:
no fuel leaks, at least we can't smell fuel anywhere and I've got a pretty good nose. Have checked vent lines for obstructon and found none.... routing looks good at first glance, may have to dig deeper on this one however.

rv8r999:
he is burning stricktly 100ll...he does not have a fuel flow meter.

walt:
thanks for the fuel line "flap" heads up...will start taking off fuel lines and checking.

smo:
cam issue is interesting but wouldn't a worn cam continually show a low pressure and not be intermittant?

rfazo:
doesn't matter how much fuel on board or which tank is selected, it does it with both tanks. interesting you see yours drop to as low as .5 with no issues or concern... we have always boosted back up with the electric if we see it this low in fear of it quitting. we have seen the pressure drop to .5 in straight and level flight also.

n816kc:
pulling air without leaking! I hadn't thought of that... is that really possible? May be something to look into....Just thinking out loud here but if the original builder had flared some of the tubing with the wrong angle or just had bad flares could they possibly pull in air without leaking?

sam:
thanks for the float issue, we may be looking into it but i'm not sure how this could show up as low pressure between the engine driven pump and the carburator.

drycreekrv:
Sorry you are having the same issues but on the other hand it is good to know we are not alone. Have you already replaced the engine driven fuel pump once and going for your 3rd one?

ron:
didn't replace the facet fuel pump we replaced the engine driven pump. Facet may be next however.

foka4:
I agree about running the facet fulltime, but if it quit and the engine driven pump wasn't producing....I don't want to be in that airplane. We have thought about putting a second electric pump in line so we now have three fuel pumps 2electric and the engine. Run one electric fulltime along with the engine pump and use the second one only if the first one finally reached its limit and quit during flight. I would rather find the problem and fix it instead of just putting a band-aid on the situation however.

thanks again, keep the ideas comming!

doug
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  #19  
Old 06-29-2011, 08:27 PM
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Mark Burns Mark Burns is offline
 
Join Date: Jan 2005
Location: Ruston, Louisiana
Posts: 879
Default Something to check

Doug,
I didn't read everything in every post but I'm leaning toward the "air leak" that some posters mention.

One place that this could happen is the gascolator O-ring. It could be damaged and rolling or something. It could let air in but keep fuel from leaking. I'd check it good and put some fuel lube on it.

Ok, I went back and read more of the posts and the gascolator seal has ben mentioned already.
Check it twice!

Good luck.
Mark
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Last edited by Mark Burns : 06-29-2011 at 08:32 PM.
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  #20  
Old 06-29-2011, 09:55 PM
DENMACRES DENMACRES is offline
 
Join Date: Aug 2008
Location: MONTGOMERY, TX.
Posts: 89
Default fuel

Be sure and check that the vents are open and face forward.
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