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Better fuel consumption on 503 ?

Posted: Tue Mar 17, 2009 11:26 am
by Maybe
Hi,

I've noticed an increase in fuel consumption on my Rotax 503 trike.
Its been operated from the same elevation as always (3700ft). But it seems it is burning 15l/h now when I'm flying solo. (That is in a cruise config - 1 take off and 1 landing).

Any ideas?
Can it be the season that is changing?

In general: What can be done to achieve better fuel consumption?

Re: Better fuel consumption on 503 ?

Posted: Tue Mar 17, 2009 12:34 pm
by Morph
Wear and tear in the carbs, the jet needle in particular vibrates a lot if the little rubber ring is not inserted. This wears the sides away and more fuel is allowed through.

The engine becomes worn and less efficient. You might have a slight fuel leak, spark plug gaps not right, air filter blocked.

Sounds like it needs a good service

Re: Better fuel consumption on 503 ?

Posted: Tue Mar 17, 2009 12:48 pm
by Maybe
Thanks for the reply Morph.

I'll go and have a look at the needle jets. (I've replaced them about 100 hours ago)
I have the little rubber ring installed.
Spark plugs replaced 3 hours ago. The gap is as they have set it for me at Aviation Engines when I bought them. (what gap do you suggest?)
I'll go clean my airfilters and apply K&N Spray-oil again. (I've cleaned them about 25 hours ago).

Regarding the fuel leak...mmm probably difficult to find? I'll have a look if I can see anything.

thanks again!

Re: Better fuel consumption on 503 ?

Posted: Tue Mar 17, 2009 2:15 pm
by Wargames
It is not necesarily the engine, My vote goes to your wing.

Get a batten profile sheet, and bend your battens according. That should solve the problem.

As you fly your battens tend to loose there shape and subsequently you will loose lift, and thus the extra fuel to keep you in the air.

I sent my wing to solowings in october last year. Before hand, my fuel consumption was about 15 as well, and afterwards 10.

Let us know.

Regards,

Re: Better fuel consumption on 503 ?

Posted: Tue Mar 17, 2009 8:51 pm
by kloot piloot
Hw'zit Maybe, your question,
Can it be the season that is changing?
I stay in the Brits area at same altitude. It's become colder lately, and this should improve your engine's performance and consumption. If you did what Morph and Wargames suggested then maybe your foot might have become a bit heavier in the circuit ? Steeper climbing and turning, throwing the aerie around a bit ?

I have found that 16l/hr is not uncommon when "playing" around the field. vhpy