582 Rotax Fuel Consumption - advice please!

[John.com]

Fellow 582 Rotax Owners or APOs!

I am concerned in that my Rotax 582 (silver top) fuel consumption rate appears to have increased gradually over the past six months. My engine is at 700 hours and I have never done a 'carb service'. When I raised the issue with Comet Aviation Supplies they immediately recommended a carb service. BUT, the parts for a carb service are R3,500 and so would like to get some advice before going this route.

Firstly, can you give me an idea of what your fuel consumption is:

a. At take-off/in a climb?
b. In the cruise?

Secondly, what advice is there for reducing high fuel consumption?

I have tuned my carbs in accordance with Paul Mulders' notes (thanks Paul!) but am still at 24l/hr in the climb and 14l/hr in the cruise! EISH! Fuel prices are killing me!

This is what the Rotax 582 manual shows:

Rotax 582 Fuel Consumption.png (34.25 KiB) Viewed 9956 times

So according to this my fuel consumption does NOT appear high, but I am convinced it is and that I was flying a lot more economically six months ago!

I would greatly appreciate any advice.

John.com

[Sukkelaar]

What you are burning sounds about right. 2 stroke rotax are fuel guslers. Might get better fuel burn if its not a trike, but not much better.

Regards

[D2O]

Silly question, but old plugs maybe?

[Triker]

Dont worry too much John, it sounds fine.

A recent trip with the Cobra, full tank(83l) and 1 pax gave me a fuel consumption of overall 25l/hr !!
With only one in between stop at Rhino Park. It was in the early mornings when air was nice dense
I filled her up when i took of with gauge at 99% and 1 hour 57 minutes later i stopped at Kitty with 40% tank left
thus 60% of 83L (49,8l) and 2 hrs flying time gives you 24.9l Ouch!!!

I know fuel prices are killing us.
Now you can be rest assured. Wish i had your fuel consumption

[mulderpm]

Hi John,

Your consumption sounds about right. I have a fuel flow meter on my 582 which gives me real time consumption. It is not 100% accurate but close enough. Taking a pax adds about 3-4 l/h. What I did notice is that the higher consumption is not really an engine rpm issue but just that the engine has to work harder to achieve the rpm. I cruise at about 5000 rpm dual or solo but the fuel burn is lower solo. Case in point, if I dive and keep the rpm at 4500 she burns 4 l/h. Idling stationary on the ground burns 7-8 l/h, horrific aint it. When taxiing it drops to 4 l/h.

Solo cruise - 5000 rpm @ 10 l/h
Dual cruise - 5000 rpm @ 14 l/h
Solo Max climb- 6450 rpm @ 25 l/h
Dual Max climb - 6450 rpm @ 28 l/h

It is true that the carb jets become worn bigger over time and this will increase fuel consumption. I replaced my main jets, needles and needle jets at 150 hrs and will do this again at 300 hrs. Costs about R700. I can not say that I noticed any change after replacing them but, for safety sake, I do what the manufacturer recommends.

[John.com]

Hi John,

Your consumption sounds about right. I have a fuel flow meter on my 582 which gives me real time consumption. It is not 100% accurate but close enough. Taking a pax adds about 3-4 l/h. What I did notice is that the higher consumption is not really an engine rpm issue but just that the engine has to work harder to achieve the rpm. I cruise at about 5000 rpm dual or solo but the fuel burn is lower solo. Case in point, if I dive and keep the rpm at 4500 she burns 4 l/h. Idling stationary on the ground burns 7-8 l/h, horrific aint it. When taxiing it drops to 4 l/h.

Solo cruise - 5000 rpm @ 10 l/h
Dual cruise - 5000 rpm @ 14 l/h
Solo Max climb- 6450 rpm @ 25 l/h
Dual Max climb - 6450 rpm @ 28 l/h

It is true that the carb jets become worn bigger over time and this will increase fuel consumption. I replaced my main jets, needles and needle jets at 150 hrs and will do this again at 300 hrs. Costs about R700. I can not say that I noticed any change after replacing them but, for safety sake, I do what the manufacturer recommends.

Thanks a lot Paul (and others!).

This makes sense and is in line with my current fuel consumption rates.

You've just saved me R3,500!!

[bobthebuilder]

As a matter of interest, did you move your wing at the hang point?
Eaten a few too many biscuits lately?

[John.com]

As a matter of interest, did you move your wing at the hang point?
Eaten a few too many biscuits lately?

Thanks Bob!

To your first point, no.

To your second point . . . . yes, one or two! HaHa! Maybe your comment is what I needed to kick-start my 2013 fitness drive!!

[Bundy]

Morning Bushwacker

John, your consumption seems about right to be honest.

With DBP, the lowest average consumption I get is about 12-13L per hour (Cross country ) but believe me...when doing circuit work with fullthrottle climbs etc etc she's a thirsty beast and then it shoots up to 17-19L per hour average.

I am usually far more concerned with the fact that the engine is still running than my actual fuel consumption!

To be on the safe side when flight planning, I always work on an average of 15L....best to land with more fuel than you thought you'd use is the way I think about it.

We missed you at Aeroden the other day?

[John.com]

Hey Alan!

Thanks for your views on what these 582s guzzle, which are now confirmed by most.

If nothing else, I plan to shed those "few extra biscuits", as Bob so politely pointed out!

Sorry I missed you guys at Aeroden. I was close by, helping a fellow pilot de-rig her wing.

Next time let me know your plans to visit and I will make sure I am there welcome you.

Cheers, John.com

[Turbo]

Was chatting tomPaul ki

Kingsley - his cheetah runs a 582, and he uses 14 L/ph - it seems your engine is on par with the norm

My cheetah has a 912 EXTRA in it and uses no more than 10litres an hour doing touch and goes in training, this was surprising to both me Paul and I -- I was expecting 16 - 17 L/ph

Two strokes most certainly use more fuel than 4 stroke engines, confirmed once again with our motor cross bikes.

[John.com]

Was chatting tomPaul ki

Kingsley - his cheetah runs a 582, and he uses 14 L/ph - it seems your engine is on par with the norm

My cheetah has a 912 EXTRA in it and uses no more than 10litres an hour doing touch and goes in training, this was surprising to both me Paul and I -- I was expecting 16 - 17 L/ph

Two strokes most certainly use more fuel than 4 stroke engines, confirmed once again with our motor cross bikes.

Many thanks for this info!

[KFA]

If you say the fuel burn increased over a period then something changed or is changing. The consumption might still be on par with others but YOUR engine is not the same so it needs to be invetigated. It is recommended that the needle jet and jet needle of the 582 and 503 be replaced at 150hr intervals.

Assumption is the mother of all buggerups. Investigate the problem. I would just replace the jets and needles. They are cheap. I am sure the price quoted by AV engines will include slides and so on which you do not need to replace at the moment.