jetjr Posted June 15, 2009 Share Posted June 15, 2009 Older versions with wing tanks have fuel taps for each side but this was a problem as the aircraft was not certified and tested with one tank full, one tank empty IF a pilot screwed up and sucked a tank right out it could enter a spin??? Not sure how real this potential is but the taps were deleted or the handles were removed. I have the visual guages (and the taps) and when the guages get a long way out just turn lower reading one off and they equalize within minute or so. This tells me it is an indication error not actual unbalance. Although I have had big differences upon refilling occassionally. Even when one tank goes right below bottom of sight glass, turning it off brings fuel back up the glass??? to about where it should be Also using electric fuel pump helps draw tanks evenly especially when levels are very low How long does the engine run for with the header tank light on? JR Link to comment Share on other sites More sharing options...
Guest brentc Posted June 15, 2009 Share Posted June 15, 2009 Don't think you would enter a spin if one tank ran dry. If you did, you'd be in trouble and would always have to fly with a passenger to even out your load, particularly if you're a fattie! I've got the old system with 2 taps. It gave a lot of issues when a pilot would let a tank run dry as the engine would suck in air and stop abruptly! hence the introduction of the header tank. That wasn't without issue, even the factory Jab had an engine out on the way to Narromine after it was fitted due to the vent configuration. Link to comment Share on other sites More sharing options...
jetjr Posted June 15, 2009 Share Posted June 15, 2009 Brent, I agree with the spin recovery thing, but I heard it wasnt tested in this configuration so therefore no good. What was the story behind the Gascolator/ central vent in the roof idea mine had originally - got changed and a header tank fitted at some stage, hope they got the venting right the second time round? Does anyone have a fuel system layout for earlier J200 with header under pax seat? JR Link to comment Share on other sites More sharing options...
Jabiru Phil Posted June 16, 2009 Share Posted June 16, 2009 How long does the engine run for with the header tank I am told as soon as the tank starts to empty. 5 litres capacity I ran one tank dry in my old 230, gave a few coughs and came to life as soon as I switched tanks and fuel pump on, 10 seconds at the most. Full load and no indication of wing drop.(one tank full) The habit I got into was to turn one tank off after take off and change around after half an hour or so to keep tanks equal. Human factors i.e dodging rain squalls and navigating was my excuse. As I was near to land at home it could have happened in the curcuit a different result may have resulted. One scenario with the two (actually three ) fuel tap system on home built 230's is that if you leave the two main tank valves off you then only have the header tank alive which only gives you a few minutes in the air depending on warm up time. As opposed to Factory built which only runs the carbie bowl empy in less than a minute. Hope this helps. Phil. Link to comment Share on other sites More sharing options...
Jabiru Phil Posted June 16, 2009 Share Posted June 16, 2009 JR, Send me your email address and I will forward pdf file on header tank. Phil. Link to comment Share on other sites More sharing options...
Cosmick Posted June 19, 2009 Share Posted June 19, 2009 My 2 cents worth. I've been looking around coming to grips with what fixed wing aircraft I would like to own. I've only flown in a few Tecnams, Savannagh's but all powered by Rotax (also my own 503). I like the look of the Jab's and Aussie and better Qld product BUT I look at the For Sale adds and many have different hours Engine to airframe etc and not big airframe hours, new heads etc. This is even aparent on the Jab site. From reading this thread I can see many people love their Jabs and a lot are very hands on mechanically and maybe thats what Jabs need. For me, I don't want to increase risks of engine out unnecessarily especially as my kids are most likely my passengers. I wont buy an aircraft powered by a Jab motor, I understand the process of time and use to make them better and i'm sure they are a lot more reliable now than previous BUT for me i'll go Rotax. Pity Jab don't have a rotax option. Link to comment Share on other sites More sharing options...
Yenn Posted June 20, 2009 Share Posted June 20, 2009 There is at least one Jab with a Rotax 912 motor. I saw it at Old Station 2 years ago. Link to comment Share on other sites More sharing options...
Guest brentc Posted June 20, 2009 Share Posted June 20, 2009 There's a J400 at Tumut with a 914 and constant speed prop. Link to comment Share on other sites More sharing options...
winsor68 Posted June 20, 2009 Share Posted June 20, 2009 Pity about the non-Rotax issue...the odd one or two doestn't really count... Link to comment Share on other sites More sharing options...
dazza 38 Posted June 20, 2009 Share Posted June 20, 2009 Hi cosmic, rotax 912,s constanly make it to tbo. It would be interesting to find out how many jabiru engine make it to tbo Link to comment Share on other sites More sharing options...
HEON Posted June 21, 2009 Share Posted June 21, 2009 Just been on a long trip (2250nm) in company with J160. When cool in morning it would not start, requiring entra battery assistance (a bit of a problem in the outback without jumpers etc). After a bit of a warm up no further problems during the day. Is this a common problem? (about 600hr, and no the battery tested OK) Link to comment Share on other sites More sharing options...
jetjr Posted June 21, 2009 Share Posted June 21, 2009 Im assuiming youve carried out the service bulletin regarding this issue All good so far after doing this JR Link to comment Share on other sites More sharing options...
Yenn Posted June 21, 2009 Share Posted June 21, 2009 The hard starting is all down to the battery not being man enough. Most Jabs use Odyssey batteries and they advertise that they have good cold cranking amps. That is to my mind false advertising. My battery is 13 months old and has to be helped most winter mornings. Yesterday it started the engine OK, today, no show. The Jab needs about 300rpm to get a spark. A bigger battery may help, but the cost is excessive. Link to comment Share on other sites More sharing options...
Guest brentc Posted June 21, 2009 Share Posted June 21, 2009 I used to think that the battery was at fault for the poor starting but now I firmly believe that it has nothing to do with it. As long as the Service bulletin has been complied with for relocation of the earth lead straight onto the starter versus the engine, then there will be no problems to at-least -5 deg temps. Mine would rarely start sometimes even with a jump start unit at 10-15 degrees, but since the SB it has never let me down right through winter. Link to comment Share on other sites More sharing options...
Jabiru Phil Posted June 22, 2009 Share Posted June 22, 2009 I used to think that the battery was at fault for the poor starting but now I firmly believe that it has nothing to do with it. As long as the Service bulletin has been complied with for relocation of the earth lead straight onto the starter versus the engine, then there will be no problems to at-least -5 deg temps. Mine would rarely start sometimes even with a jump start unit at 10-15 degrees, but since the SB it has never let me down right through winter. We have two 230's here, one with the larger battery and still cold start problems as with the other with standard battery. We have tried everything, including wiping down moisture on fly wheel to adjusting choke and no fuel pump prior to start. I was at Rawnsley park the other day on the way back from the Lake and both planes would not start until we poured HOT water from a thermos (that I alway carry now) on top of the carbie- instant start!! The temp was around +7-8 deg and probably colder earlier but not below 4 deg. I am seriously considering installing another trap dood similar to the oil inspection door to allow HOT water to be applied without removing the cowl. I will go down this track unless there is a another solution. All sb's carried out. I hope that someone will find a solution. All indications point to Fuel starvation at start up. Same problem yesterday. Phil. Link to comment Share on other sites More sharing options...
Guest brentc Posted June 22, 2009 Share Posted June 22, 2009 I used to have starting problems when my aircraft was cold and later found out that the choke wasn't coming on fully when the cable was pulled. That problem, combined with a too large plug gap and the mis-placed earth from the battery were all working against me. My current cold-starting procedure is to: - Turn the prop a few times and feel for the compressions - Pull the throttle completely back (make sure it's ALL the way off) - Choke hard on ensuring that it's really on - Fuel pump on Crank away. It's never let me down yet (since the earth changes). I am using a large main jet now but that probably doesn't mean much. I can't stress the importance of the throttle being all the way off when the choke is applied - they simply don't work together! Link to comment Share on other sites More sharing options...
slartibartfast Posted June 22, 2009 Share Posted June 22, 2009 I had trouble for a while. Part of it was an Odyssey battery which broke within 6 months, but the problem still existed for some time, and wouldn't start cold without an external jump pack. Some clues lead me to check out the solenoid (the final clue was the earth return from the solenoid catching fire). I replaced the cheap Jabiru one with another identical unit I found at Supacheap Auto while sourcing a better one. The Supacheap one didn't work much better, but since installing a quality unit I have had no starting troubles at all. First time everytime - once I turn the ignition on (I usually crank it a bit before starting). This is without doing the SB on the starter earth. My testing indicated that my setup was working fine. The battery is a Deka and has tons of cold cranking power. Link to comment Share on other sites More sharing options...
Derby Posted June 22, 2009 Share Posted June 22, 2009 Hi my J400 has 300 hours on it I have never had a problem with starting. I open the throttle about 1/4 inch fuel pump on for about 10 seconds and hit the start button it has never failed to start. ps I never have to use the choke, even winter. I have not carried out the change to the starter earth . Rory Link to comment Share on other sites More sharing options...
quentas Posted June 22, 2009 Share Posted June 22, 2009 I used to carry `start yer barstard` and did the hot water thingy UNTIL I got a Deka Battery. Now the starter goes harder for longer and with the choke on `hard` just until it fires and runs. No more embarrasing cold mornings with the cowls off and technams cruising past laughing and pointing. Link to comment Share on other sites More sharing options...
Ultralights Posted June 22, 2009 Share Posted June 22, 2009 funnily enough our LSA doesnt have any probs starting, and we never use the choke, if it hasnt started by the 4 turn of the prop, just pull the carby heat. starts every time.. Link to comment Share on other sites More sharing options...
Guest brentc Posted June 22, 2009 Share Posted June 22, 2009 if it hasnt started by the 4 turn of the prop, just pull the carby heat. starts every time.. Would you care to explain to me how that would actually work on a cold engine??? Link to comment Share on other sites More sharing options...
motzartmerv Posted June 22, 2009 Share Posted June 22, 2009 ??...Carby heat??... doesn't carby heat use the heat from the engine to work?/...as in, an engine that has been running? Link to comment Share on other sites More sharing options...
IanR Posted June 22, 2009 Share Posted June 22, 2009 Maybe there is an secondary effect of the carby heat other than the expected hot air that works in his situation - it certainly wouldn't provide hot air from an unstarted engine ! However it does usually reroute the air intake and provides unfiltered air so maybe that changes the mixture enough in that situation to fire at cranking revs ? Just a thought ! Link to comment Share on other sites More sharing options...
Guest ozzie Posted June 22, 2009 Share Posted June 22, 2009 Maybe as the flap swings thru the mixer box it 'chokes' the engine just enough to give it that first fire to kick it along. Link to comment Share on other sites More sharing options...
Guest drizzt1978 Posted June 22, 2009 Share Posted June 22, 2009 And remember, all engines have there on personality ;-) I had a jaguar once, you had to swear at it before it started..... Link to comment Share on other sites More sharing options...
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