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Rotax 582 Blue top

Guest marbrody

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Guest marbrody

As you may know I fly my Drifter out of Armidale all year round.


I have the needles in the twin Bing Carbies set to there leanest settings due to my altitude here and the altitudes I fly cross country at.


However Now it is getting warmer, I may fly down to the coast, and my question is; how will this effect my engine say over a weekend jaunt @ sealevel.


Should I be riching the mixture up before departure?



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Guest Andys@coffs

Currently I fly an Airborne Trike with a freshly overhauled Oil injected 582. Why freshly overhauled.... It seized turning crosswind about 18 months ago. Very expensive and ultimately because it was too lean.


A slightly higher fuel usage, even at $1.45 per litre is a long way short of the $4500 required for the rebuild.


Of course it wasn't that simple, if fact it took 3 seizures in a row (2 under warranty, immediately during breaking for the 2nd and at 300ft on T/O for the 3rd) before we worked out that the EGT probes / EGT guages were under reading by about 60deg Celsius. A replacement of probes and guage with the electronic version immediately highlighted the issue and the carby jet needles were lifted. It was painful for me at the time, though after 18 months I can see significant learning that I benefited from


1) The stuff the instructors went on about the fan can stop at any momement..... well nothing focuses that thought more appropriately than having been in that position. that shortcut across tiger country no longer seems so appealing.


2) The stuff that the instructor taught me worked. landing across 05 at Gawler with a 25kt tail wind was interesting, as was the wire fence that was racing at me, still I stopped in time with no further damage


3) Mechanics are good, nut not infallible, while warranty covered the parts for 2 and 3, I paid the labour and the fact that I lost one oversize piston potential. I'm on the last oversize now and all for about $50 worth of cheap parts (guage / sender) and a failure of back to basics fault finding.


Anyway enough rambling, Is there any reason to not enrichen the mixture, carboned plugs and increased fuel econ are small price when compared against the $4500 bill and that doesn't consider the value of your life.


Andy Andys@Gawler



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Guest micgrace



In reply, this is a must do. The mix will lean off considerably at sea level. The fuel (petrol engines) is used for cooling purposes as well. (not well known) i.e. it takes some heat from the airflow as well as surrounding metal. Plus 2 strokes (with added oil, need it for lube.)


A trick (off the topic a bit) when I tuned some turbo EFI engines when under boost, with high inlet temperature, I deliberately set the fuel (higher than what is required) injection quanity: air temp so to bring the air inlet temp down somewhat to control detonation. This trick is not well known either.


Just an idea. Micgrace:)



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  • 4 months later...

Altitude Compensation




I hail from the coast in South Africa (Durban) there are many 503/582 motors flying here. As you may know Johannesburg is 6,000 ft above sea level. Without exception all owners that migrate to the coast change jets on arrival. Maybe post a thread in technical talk microlighters.co.za and advise your altitudes and you will get all the answers in fine detail. Also you will get other altitude power sapping mods the guys do.


I fly a HKS which has altitude compensating carbs (same as 912).


Good Luck





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