Fuel not flowing from left wing tank...

[John Womer]

New owner here. Picked up N731J (2010 J230-SP) in Shelbyville ten days ago and flew home to KOXC (Oxford, CT).

 

We left Lynchburg, VA with a full fuel load, the three fuel shutoff valves (left, right, main) all ON, and the fuel gauges on the G3X reading full for both tanks. A few hours into the flight we noticed that the right tank level was dropping faster than the left. By the time we got home, the right tank was reading much lower than the left.

 

Got out my new Jabiru fuel stick this afternoon. Left tank reads 15 gallons... right tank no reading on the stick at all. That tells me I've got a blocked/pinched fuel line.

 

Anyone else had this issue with their Jab?

 

Thanks in advance for any guidance.

 

 

[brilin_air]

Hi John,

 

I have had a similar situation and it has been cured by flying with the balance ball more to the side that the fuel tank is draining from, maybe the balance ball guage was fitted slightly offset, the other thing to check for is that you don't have an airlock in the fuel hoses, if you take the filler caps off and lift one side of the aircraft slightly you should be able to siphon fuel from one side to the other and back again, also check if the breather posts on the filler caps does not have a sticking ball in them.

 

Hope this helps

 

Brian

 

 

[Jaba-who]

Even when everything seems to be correct it seems to be common for jabs to empty one tank faster than the other. Mine drains left tank faster than right. I can't remember if it was on this forum or another that there was a discussion and seems to be a common occurrence.

 

 

[frank marriott]

My experience is it is all about balanced flying.

 

In smooth air and keeping the ball in the middle I have even fuel flow.

 

In turbulance with the ball bouncing around I get an imbalance but can level the tanks by introducing a small amount of pro rudder .

 

In John's case after parking overnight with all taps on then the fuel should be equal [providing the ground is flat] & he hasn't got a blocked/pinched fuel line which he referrs to.

 

The tanks are too long and flat for accurate readings by dipping the tanks

 

FrankM

 

 

[Jaba-who]

Quote "In John's case after parking overnight with all taps on then the fuel should be equal [providing the ground is flat] & he hasn't got a blocked/pinched fuel line which he referrs to."

 

Unfortunately some exceptions to that exist. A partial blockage can produce even tanks in the morning provided enough time has elapsed. I'd be giving the fuel lines a good inspection for kinks or "u" bends (as per jabiru service bulletin)

 

 

[fly_tornado]

Don't forget the Jabiru was designed and tested in the Southern hemisphere http://en.wikipedia.org/wiki/Coriolis_effect

 

 

[Jabiru Phil]

I used to have the 3 tap model and found it better to only use one tank at a time, especially with full tanks as lost fuel can be quite considerable when out of balance.

 

Use your gps to half hour reminder re change tanks.

 

The newer model also has dash gauges and flying out of balance vnen slightly will transfer to one tank and empty it with the excess supply overflowing from the breather.

 

I no longer completely fill my one tap model due to this problem.

 

Regards,

 

Phil.

 

 

[frank marriott]

Phil

 

The slight out of balance I was talking about was ONLY to even out the fuel, not to continue doing it so as to fill the the other tank. Maybe thats a better explanation.

 

FrankM

 

 

[John Womer]

Many thanks, guys.

 

I'll definitely check into/experiment with all that you suggested.

 

Actually, I am still working towards my license. I started training for my PPL in a Diamond DA40, then decided to go for an SPL to avoid the hassle and expense of getting a "special issuance" 3rd class medical certificate. And since there aren't any LSAs available to train in near hear (and I planned to eventually buy my own plane anyway) I bought the J230 to both train in and fly afterwards. Most of our flight was at night, so my CFI did most of the piloting. And while we did have a left quartering headwind most of the way, he kept the "ball" in the center the whole way -- at least according to the G3x EFIS.

 

I'll let you all know how I made out and, again, thanks.

 

 

[compsci]

It is not unusual for the tanks of the J230 to drain unequally. However, I suspect that having one tank drain completely is an indication of a problem.

 

I suggest that you contact Pete ( who is very knowledgeable about JABIRU) at JABIRU USA for his response. I have a 2009 J230 and live in a suburb north of Chicago.

 

 

[ianboag]

I have the same problem in my 160. I have been toying with the idea of partly blanking the vent holes on the fast-draining side to see if that makes a diff. In a non-critical environment of course etc etc

 

 

[Tomo]

I'd Ensure the venting holes are clear, and if you have the post on the fuel cap, the holes in are facing the right way.

 

 

[ianboag]

I'd Ensure the venting holes are clear, and if you have the post on the fuel cap, the holes in are facing the right way.

Of course. I have tried blowing through the holes too and they all seem to work .... so I just thought I'd cut down on the amount of hole on the faster-draining side and see if that makes any difference. I have at times been in situations where one of the tanks says empty ie the red light is on while tho other one seems to have plenty. Not sure how worried I should be about that ... I has a 15-minute period like that once. The engine kept going round and we landed OK. A dip seemed to show that the "empty" tank was - well - "empty" .... Go figure.

 

 

[Guest ozzie]

If you suspect an incorrect ball check the wing tips on the horizon next time you fly and level the aircraft that way. Confirm that the ball indicates the same. The other thing I'd do is a flow rate check on all three of the fuel tap settings. use a watch and a calibrated container to drain into. L/R and then both. Make sure you have the same amount of fuel in both tanks to give the same head pressure. Obviously if you have a lower flow rate from the left tank compared to the right then an investigation of the fuel/vent lines and the tap is needed.

 

ozzie

 

 

[ianboag]

If you suspect an incorrect ball check the wing tips on the horizon next time you fly and level the aircraft that way. Confirm that the ball indicates the same. The other thing I'd do is a flow rate check on all three of the fuel tap settings. use a watch and a calibrated container to drain into. L/R and then both. Make sure you have the same amount of fuel in both tanks to give the same head pressure. Obviously if you have a lower flow rate from the left tank compared to the right then an investigation of the fuel/vent lines and the tap is needed.ozzie

That would be a great idea if I had more than one fuel tap :-)

 

 

[Guest ozzie]

That would be a great idea if I had more than one fuel tap :-)

You can select one tank at a time, can't you?

 

 

[ianboag]

You can select one tank at a time, can't you?

No

 

 

[Guest ozzie]

hmm i'd be looking at a new design for the plumbing. A Nan Chang i flew in had that habit of draining one tank faster than the other. Once a faster flow rate started from one tank the other refused to flow at all into the little header until the faster tank ran out. There would be a slight pause in the procedings until the other tank got flowing again.

 

What may be going on here is one fuel line may be longer or is routed higher at some point than the other causing favor to the easier flowing line.

 

 

[jetjr]

A few ideas

 

Running electric pump 100% of the time helps

 

Dip sticks in Jabiru wing tanks are a waste of time unless nearly full

 

Quite common to draw down unevenly but usually evens out after one gets low enough

 

Even a tiny out of balance situation makes it worse

 

Can get air locks after sideslipping on take off or landing, usually rectifies itself

 

Have the low fuel light sensor installed in header tank, youll have 10-15minutes warning if serious problem arises

 

In your case there could be a high or low spot in either fuel or vent hoses - kink also maybe.

 

 

[Tomo]

What may be going on here is one fuel line may be longer or is routed higher at some point than the other causing favor to the easier flowing line.

I reckon you could be onto something there Ozzie, good point.

 

 

[johnm]

I think you can tell if you are flying balanced or not - an instrument sort of confirms it

 

So ianboag we have to assume that both your legs (outer) - those connected to your hips are the same length (left and right shoes are allowed) ............... and balanced flight is achieved

 

I'm with ozzie - I reckon its hydraulics and flow and what liquids do in them there pipes

 

As to fuel management ........................ that's probably what concerns you - you'll need some more fuel taps ?

 

Prior to modification - I'd empty the favoured tank and ground rum it and see what happens - then I'd leave it alone and see if fuel drains to the favoured tank ?

 

JM

 

 

[frank marriott]

Trust me - keep it in balance and there is no problem. Every J230 [that I know about] is the same.

 

I have spoken to [i know it's secondhand] to a bloke from Vic who has made a rudder trim fitted to the top of the nose leg on his J230 and now flies for 4 plus hours with even fuel burn.

 

If you don't believe me try it - and be very self critical for exact balance - you may be surprised. For long trips in turbulance this too much work load so the use of a small[only half a ball] out of balance every hour or so for about 10mins solves to issue.

 

FrankM

 

 

[jetjr]

I had an unbalanced fuel issue too, thought I was flying balanced using much concentration on balance ball.

 

Fitted Roll autopilot running from Dynon screen, aircraft "felt" like it was flying one side low but magically fuel drains evenly now. (except for TO and landing involving sideslip)

 

 

[John Womer]

Talked with my CFI who flew the plane back. His recollection is that the gauges were almost even when we landed and that the issue may well be as simple as the hangar floor not be as level as it looks. I've topped off both tanks and, if the weather cooperates, we'll have her in the air tomorrow and see how that goes.

 

 

[John Womer]

Apologies for not replying until now...

 

The problem was that the check valve in the right wing root... It didn't have the "bleed" like the left one did. Replaced both with new Andair check valves with the "bleed" and tanks now stay dead even.