I am getting ready for my inspection and while doing some taxi tests I noticed that my throttle slowly creeps inwards, thereby increasing rpms when I'm not expecting or wanting it.

It would seem to be the spring on the carbs being too tight. I wonder if removing a link would help or is that really stupid?!

Anyone else ever have this problem? Suggestions? It's a Rotax 912 ULS if it matters,



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don't remove a link. you have to have a locking/friction  throttle of some sort; if you already have that the friction needs to be somehow increased. It's normal and it's up to the builder to use one of the common decades old methods to control it. Plans/install manual...

Just tighten your friction adjust lock so you can push it in and out but won't pull forward with the throttle springs. Mine with no friction lock will pull forward increasing my RPMs very easily. So keep your hand on the throttle while you are landing or it will creep up on you and you'll never land! Good luck with your first flight, you are going to love it.

I'll go back and see what I can do with the throttle cable for tightening the friction lock. Though reading the Rotax owners forums I see some people have replaced their springs with these ones that are made for exactly this problem.


I was having problems keeping my carbs synched and didn't like the throttle creep either. I bought the first dual cable for the 912 that Mcfarlane manufactured and that solved all my problems. Synched the carbs and haven't touched them since and the friction lock works just right. I recommend it...yeah it's $$ but IMO worth it. I thought the springs were too strong too but got no complaints now it just becomes a matter of technique and getting used to it. Somebody, I think it was Jon Croke, cut a round off his and they didn't advance on a go around or something like that and he piled it up. Ask around, I forget. I like the factory springs. Stout but reliable and those strong springs are what keeps your carbs synched.



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