Tuning Rotax 503

[Alpha]

Hi All,

I am hoping someone here can help...Ducky..I am hoping for some words of wisdom here...

I have a rotax 503 (duh??) All setup correctly , well according to me that is. However I have one problem...I cannot achieve the correct Max RPM when on the ground...Max I get 5950rpm...

I have recently changed my prop...but i cannot believe that would be the reason...I used to have a 63X34 P Prop and now I have a 63 X 35...I don't think the 1 inch change in pitch will make such a huge difference. There is a guy in my hangar that swing swings a 72 X 35, so I don't think it is the prop length either...

The answer to the problem could lie somewhere in the fact that my fuel consumption at cruise (5500) is about 19-20l/hr...

Carbs balanced and synchronised...idle perfect at 2080rpm...Pllllleeeeeeeaaaaassseee Help!!!...

[German]

Jets?

[HENNING JOHAN]

Hi All,

I am hoping someone here can help...Ducky..I am hoping for some words of wisdom here...

I have a rotax 503 (duh??) All setup correctly , well according to me that is. However I have one problem...I cannot achieve the correct Max RPM when on the ground...Max I get 5950rpm...

I have recently changed my prop...but i cannot believe that would be the reason...I used to have a 63X34 P Prop and now I have a 63 X 35...I don't think the 1 inch change in pitch will make such a huge difference. There is a guy in my hangar that swing swings a 72 X 35, so I don't think it is the prop length either...

The answer to the problem could lie somewhere in the fact that my fuel consumption at cruise (5500) is about 19-20l/hr...

Carbs balanced and synchronised...idle perfect at 2080rpm...Pllllleeeeeeeaaaaassseee Help!!!...

Hallo,Gary!I had a 63x34 geo kelly prop on cai with a b-box.Max rpm in the air was 5850.I got now a ivo prop and it gets 6300rpm.Carbs was rebuild 1year and 3 months ago.My trike also idle around the rpms that you have.I think it is the prop.Regards Johan. That 72x35 is maybe a c box?

[nickjaxe]

A 1 inch difference in pitch will make a huge difference...and the engine needs to make its stated RPM,

To course a pitch with a 2 stroke and it will run rich...to fine and it will run weak with associated high EGT,

What tach where you using...a/c tach can be quite a few hundred RPMs out....and what type of a/c is it.

Nick.

[Duck Rogers]

I might be going your way this coming weekend.
You want me to come and fix it?
It will cost you a hamburger and a coke
and if I can't fix it, I'll "return" the hamburger..

[Alpha]

Hahaha @ duck,

If you are in the area that would really be appreciated... As for the hamburger... No returns haha!!!

Duck, your help would really be appreciated. Thanks