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KitFox Fuel Starvation

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Dale Orth

Joined: 11 Aug 2008
Posts: 13
Location: Las Vegas,Nv

Posted: Mon Aug 11, 2008 3:21 pm Post subject: KitFox Fuel Starvation

I just bought a KitFox 7. Flying it home I experienced low fuel pressure on the digital readout 3 different times. Do 912's vapor lock?? Is the Fuel Pump going out?? Even with the Boost Pump the pressure was low. It always happened after about 2 1/2 - 3 hrs. of flight. Any ideas???

gary.algate(at)sandvik.co
Guest

Posted: Mon Aug 11, 2008 3:34 pm Post subject: KitFox Fuel Starvation

Probably a stupid question but are the breathers in your fuel caps clear? 

 

regards 

 

Gary

 

 Gary Algate

 Classic 4 jab2200A

 Office Phone: +61 8 8276 7655

 

 

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"Dale Orth" <daleorth(at)embarqmail.com> 

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12/08/2008 08:59 AM 

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--> Kitfox-List message posted by: "Dale Orth" <daleorth(at)embarqmail.com>

 

 I just bought a KitFox 7. Flying it home I experienced low fuel pressure on the digital readout 3 different times. Do 912's vapor lock?? Is the Fuel Pump going out?? Even with the Boost Pump the pressure was low. It always happened after about 2 1/2 - 3 hrs. of flight. Any ideas???

 

 

 

 

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 [quote][b]

Dale Orth

Joined: 11 Aug 2008
Posts: 13
Location: Las Vegas,Nv

Posted: Mon Aug 11, 2008 3:41 pm Post subject: Re: KitFox Fuel Starvation

My fuel cap vents are wide open. I'm going to watch it closely and when the red light comes on I'll keep the power up, over an Airport of course and see if I lose power. If I don't lose power it might be a sending unit problem. Thanks for the response.

Dale

kirkhull(at)kc.rr.com
Guest

Posted: Mon Aug 11, 2008 3:46 pm Post subject: KitFox Fuel Starvation

My first check would be the fuel vents in the caps



--

rdmac(at)swbell.net
Guest

Posted: Mon Aug 11, 2008 4:08 pm Post subject: KitFox Fuel Starvation

I would check the fuel filter.



Roger McConnell, Duncan, OK

Model 7 Trigear, Rotax 912uls 

Flying sense Jan. 06



--

lcfitt(at)sbcglobal.net
Guest

Posted: Mon Aug 11, 2008 5:35 pm Post subject: KitFox Fuel Starvation

Dale,



What were the fuel pressure readings?  Did the engine act like it was fuel 

starved?  Did you notice higher than normal EGT temps?



With the 912, fuel pressures are quite low - 5 or so PSI.  If your boost 

pump puts out more than that it will push fuel past the needles in the carbs 

flooding the bowl.



I never had a fuel pressure gauge on my 912 so never had a low fuel 

indication.  But then again, never had any low fuel flow symptons either. 

In fact, I don't recall an instance over the years where someone has had an 

issue traced to fuel flow that was mechanical in nature.  Someone refresh my 

memory if I there was an instance.  There has been lots of talk of uneven 

tank drainage, but that doesn't seem to be your issue.



Lowell

---

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Mon Aug 11, 2008 6:54 pm Post subject: Re: KitFox Fuel Starvation

Hi All,



Some of the Rotax engines are just starting to show low fuel pressure. This has been happening on some of the Flight Design Ct's. I am in the process of doing some testing to rule in or out mechanical, gage or vapor lock issues. The guys doing the testing won't know for a few more weeks. 100LL does not fix the problem. I will keep you posted on my testing. This is happening to me also and has now for a month. I use a Dynon system for tracking my engine performance.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

Dick Maddux

Joined: 24 Jun 2008
Posts: 516
Location: Milton, Fl

Posted: Tue Aug 12, 2008 5:40 am Post subject: KitFox Fuel Starvation

I have been thinking of installing an electric boost pump in my 4. All I have now is the mechanical pump and I don't know if the engine would gravity feed if the pump quit. This discussion has brought the subject to light for me. 

  Does anyone have a suggestion as to the type (or brand) of pump to purchase and where to install it?

  I know in the case of my oil pressure sender, it was reading bad. I removed it and tested it with my air compressor (using a gage of known accuracy) and found the sensor was reading 10 lbs too low. I then purchased another(expensive) sensor. It is reading correctly pressure wise, but now I have fluctuations in the needle at cruise rpm which the other one did not do. I have the old Westach quad gauge and that might be part of the problem.

   I am also having an intermittent miss in my engine at cruise. It starts after about 15 minutes of flying. I suspect it is a HT lead or plug problem (plugs have 10 hrs since new) Any ideas on this?

  Also, I changed the oil a few days ago and started to remove the filter (Rotax) It spun off with the slightest pressure from my hand! I noticed that it had been leaking. It was extremely loose and could have easily spun off in flight! When I originally installed the filter, I tightened it exactly per the SB and it was tight! I have  since made up a safety using a large hose clamp and Adel clamp rubber under the hose clamp. This clamp goes around the filter and is safety wired so this won't happen again (I also torque marked the filter) Just a warning in case it might happen to you. This isn't supposed to happen  (per my Rotax school) but it did.

   Sure am getting tired of working on this engine. I dare not get too far from home base.

   I had a friend come see me at my hanger the other day. He has a beautifully restored Triumph TR8. I told him not to shut it down as it would probably break because of all the bad luck I am having. He told me that the car is running perfectly and no problem.--------

 ------- We jumped it to get it started.

  

                                                        Dick Maddux

                                                        Fox 4-1200

                                                        Rotax 912UL

                                                        Pensacola,Fl  



Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos.

  [quote][b]

kcflys

Joined: 28 Aug 2007
Posts: 33
Location: Rancho Cordova, CA

Posted: Tue Aug 12, 2008 5:54 am Post subject: KitFox Fuel Starvation

Hey Dick,

  

 I don't think I will fly around  Pensacola---

  

 Keith C.

Mod IV Speedster  912 IVO

Mather (MHR) CA

 [quote]   ---

_________________
Keith C.
kitfox wannabe
C-150
Rancho Cordova CA

Lynn Matteson

Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan

Posted: Tue Aug 12, 2008 6:39 am Post subject: KitFox Fuel Starvation

Hey,Dick, don't expect me to visit you any time soon...I got my own  

problems! : )



Lynn Matteson

Kitfox IV Speedster

Jabiru 2200

Status: "Condition grounded, but determined to try."  (Pink  

Floyd..."Learning to Fly")

do not archive





On Aug 12, 2008, at 9:40 AM, Catz631(at)aol.com wrote:



 	  Quote: 	
		   I have been thinking of installing an electric boost pump in my 4.  

 All I have now is the mechanical pump and I don't know if the  

 engine would gravity feed if the pump quit. This discussion has  

 brought the subject to light for me.

  Does anyone have a suggestion as to the type (or brand) of pump to  

 purchase and where to install it?

  I know in the case of my oil pressure sender, it was reading bad.  

 I removed it and tested it with my air compressor (using a gage of  

 known accuracy) and found the sensor was reading 10 lbs too low. I  

 then purchased another(expensive) sensor. It is reading correctly  

 pressure wise, but now I have fluctuations in the needle at cruise  

 rpm which the other one did not do. I have the old Westach quad  

 gauge and that might be part of the problem.

   I am also having an intermittent miss in my engine at cruise. It  

 starts after about 15 minutes of flying. I suspect it is a HT lead  

 or plug problem (plugs have 10 hrs since new) Any ideas on this?

  Also, I changed the oil a few days ago and started to remove the  

 filter (Rotax) It spun off with the slightest pressure from my  

 hand! I noticed that it had been leaking. It was extremely loose  

 and could have easily spun off in flight! When I originally  

 installed the filter, I tightened it exactly per the SB and it was  

 tight! I have  since made up a safety using a large hose clamp and  

 Adel clamp rubber under the hose clamp. This clamp goes around the  

 filter and is safety wired so this won't happen again (I also  

 torque marked the filter) Just a warning in case it might happen to  

 you. This isn't supposed to happen  (per my Rotax school) but it did.

   Sure am getting tired of working on this engine. I dare not get  

 too far from home base.

   I had a friend come see me at my hanger the other day. He has a  

 beautifully restored Triumph TR8. I told him not to shut it down as  

 it would probably break because of all the bad luck I am having. He  

 told me that the car is running perfectly and no problem.--------

 ------- We jumped it to get it started.



                                                        Dick Maddux

                                                        Fox 4-1200

                                                        Rotax 912UL

                                                        Pensacola,Fl



 Looking for a car that's sporty, fun and fits in your budget? Read  

 reviews on AOL Autos.

 www.matronics.com/Navigator?Kitfox-List _- 

 www.matronics.com/contribution _- 

 ============================================================

_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM

Beemer

Joined: 26 Aug 2006
Posts: 87
Location: Middle Georgia

Posted: Tue Aug 12, 2008 6:48 am Post subject: Re: KitFox Fuel Starvation

The most important item in diagnosing a problem is being accurate in determining the problem. Make sure your gauge is reading correctly, and verify it with a known, good instrument. You'd be amazed at how many people fly a bad gauge to an unwarranted landing, or wonder why the engine stopped with everything in the green. In my experience, the Westach gauges are not very good, and I worry about relying on them when I have to fly behind them. As a matter of fact, I just had an experience last weekend delivering a Pulsar with Westach's installed on a 912. The motor was fairly new, so I just ignored them for the flight.



With the wing tanks on a Kitfox, it's very easy to get the fuel system to feed the required fuel in flight without a pump. Maybe not reliably for every day flying, but at least feed the carbs with the fuel head pressure and proper tank pressure venting alone. I wouldn't design the system this way, as takeoff creates it's own problems. But once airborne and cruising, there should be sufficient fuel present at the carbs to maintain flight to a precautionary landing to somewhere with maintenance support.



A good test is to level the fuselage, disconnect the fuel lines at the carbs, and check the rate of fuel running out of the lines. I use my flow sender to check mine, and I get twice the max fuel flow I need at the engine. If you're less than 50% above the maximum required flow, I'd start checking for an obstruction, or possibly re-designing the fuel system to provide flow, water entrapment, and debris avoidance. Any old fuel filter won't do, get a good one that flows enough gas, even when clogged up. The tiny little marine clear units are a very poor choice in filters. I'd go at least 80 Microns to the header tank (auto parts store inline units), and 10 Microns after the fuel pump to the carbs (FI billet units with AN fittings).



Good luck,

Bradley

_________________
Beemer
KF2 (and now an M3!)
Suzuki G10 three-banger
Middle Georgia

Dick Maddux

Joined: 24 Jun 2008
Posts: 516
Location: Milton, Fl

Posted: Wed Aug 13, 2008 4:13 am Post subject: KitFox Fuel Starvation

Beemer,

   Thanks for the input ! I will keep plugging away on this engine.

    I took a break yesterday and went to town and bought a newer truck and a HD tv. I have been wanting to do that for a long time and sometimes getting away helps.

                                               

                                                 Dick Maddux

                                                 Fox 4-1200

                                                 Pensacola,Fl 

  



Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos.

  [quote][b]

n85ae

Joined: 14 Mar 2007
Posts: 403

Posted: Wed Aug 13, 2008 7:47 am Post subject: Re: KitFox Fuel Starvation

Is it possible that what you saw was a "Header Low" indicator light? Or

did you really see low fuel pressure?



In my Fox I get header low flickering when I get down to about 1/4 fuel

remaining. It was a bit disconcerting at first, but it is normal for the

low header light to start becoming a bit active as the fuel feeds start

getting exposed to air as the fuel in the tanks sloshes about.



If on the other hand you really are seeing low "pressure" that would be 

a concern.



Regards,

Jeff

FlyboyTR

Joined: 04 Nov 2006
Posts: 215
Location: Mobile, Alabama

Posted: Wed Aug 13, 2008 9:45 am Post subject: Re: KitFox Fuel Starvation

Dale,

There was a recall on the Rotax 912 fuel pump about a year ago.  I had one fail while flying a new airplane home for a friend!



If the indicated pressure did not change after turning on the boost pump...I would think there may be a flow/pressure sensor issue.  What was the pressure before and after the change?  Did the engine performance change?



Dick,...I think your 912 must have spent some time sitting on top of some sacred burial ground....all them haints just keep coming out!     I need to come see you!



Travis

_________________
Travis Rayner
Mobile, AL
Skystar Vixen, N-789DF
Continental IO-240, Prince P-Tip Prop
ADI-II Autopilot
AnyWhereMap Navigation with weather
www.enotam.net (My Flying Info Website)

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Wed Aug 13, 2008 11:04 am Post subject: Re: KitFox Fuel Starvation

I use a Facett solid state fuel pump for my Rotax 912-S.   The fuel pump is rated for something like 40,000 hours, costs only 40 bucks, and easy to install in series in the fuel line.   Fuel keeps going through the pump weather and the 912-S runs fine weather the facett pump turned on or off, and will keep the 912-S running in case that the engine driven pump on the 912-S ever fails.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

Dick Maddux

Joined: 24 Jun 2008
Posts: 516
Location: Milton, Fl

Posted: Thu Aug 14, 2008 4:05 am Post subject: KitFox Fuel Starvation

Travis,

   I think my engine spent it's life in an elephant burial ground rather than an Indian mound.

   It's a nice morning now and before the temp becomes unlivable again I think I will go fly.

   Come see me and I will give you a super deluxe deal on my remaining Aeroshell 15-50. You know I can't use it any more.

                                                       Dick



Looking for a car that's sporty, fun and fits in your budget? Read reviews on AOL Autos.

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