Backcountry Pilot • Mixture control for Rotax engines

Mixture control for Rotax engines

Sometimes the most fun way to get into the backcountry, Part 103 Ultralights and Light Sport Aircraft have their own considerations.
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Mixture control for Rotax engines

After my Idaho trip I decided that fixed mixture control sucks. My Rotax 582 Two stroke uses 36mm Bing 54 carbs. My mixture is set by my jetting and previously not adjustable. I am jetted for Sea level. When flying around in the Idaho backcountry at 5000ft plus I was obviously running really rich and could not do anything about it. I just installed a kit from Green Sky Adventures that allows you to basically lean the carbs inflight. I won't try to confuse you but for you gear heads that like to know how stuff works here is a link on how it works.

http://www.greenskyadventures.com/bing/ ... etails.htm

Here is some proof that it works

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Behind the panel hooked up to the HAC controller. It's basically just a metering valve.

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Looking at the carbs. The clear line is the new stuff.

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The short line that connects the two inner float bowl vents as part of the static system.

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Before leaning

EGT's just over a 1000 and fuel flow 4.9 GPH. With this engines EGT redline is 1200 and they really like to run at around 1150.

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Same conditions after leaning EGT's 1150 and fuel flow 4.1gph

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Overall panel shot.. 4.1 gph at 78 mph IAS and 5850rpm. On my Idaho trip I was burning 5.3gph at these same power settings and altitudes.

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Pulled back the power and got it down to 3.6 gph. I was indicating 72mph IAS at this power setting. I've NEVER seen fuel flow's below 4.0 gph above 5,000 rpm EVER.

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For $159 I only need to fly about 30 hours for this thing to pay for itself. Fuel costs is only one benefit..... more power and less carbon build up are a few others.
AvidFlyer offline
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Experimental Avid Flyer STOL 582 Rotax

Re: Mixture control for Rotax engines

We used a similar system on snowmobiles years ago. They work pretty well.
I personally would never use any plastic fittings on any engine. Especially one that was turning a prop :idea:
mr scout offline
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Re: Mixture control for Rotax engines

Same basic design on my Ski-doo Summit. I would not worry about the plastic. IF something comes off it just goes to rich correct?
670x offline
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Joined: Wed Jun 14, 2006 7:59 am
Location: Wyoming

Re: Mixture control for Rotax engines

I did the HACman, manual mixture control on my 701. I had the Simonini Victor 2 engine but the HACman setup was the same as the 582 since it also used the twin Bing carbs. The only thing about using clear line is to make sure it is fuel line and not food grade tubing. Food grade will have FDA or USDA stamped on it. To be sure I went to Polaris and bought their fuel line. The other thing I did, along with other owner of a powered parachute with a Rotax 582, is to use a two stroke oil call Blue Marble. It dropped the egt's on both engines. It dropped enough that you consider leaning it more. With the HACman you can do just that. It was a very good oil.
dirtstrip offline
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Lynn Sanderson (Dirtstrip) passed away from natural causes in May 2013. He was a great contributor and will be missed dearly.

Re: Mixture control for Rotax engines

670x wrote:Same basic design on my Ski-doo Summit. I would not worry about the plastic. IF something comes off it just goes to rich correct?


Yes it will always default to the rich side not lean. All the tubing came with the kit it's some pretty heavy duty stuff. I had to use a big set of side cutters to cut it.
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Experimental Avid Flyer STOL 582 Rotax

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