Greetings. Brand new wanna be pilot here. I've had my NexStar for almost 2 months now but everytime I go to take lessons it is too windy. The instructor says that winds usually calm down enough around the end of June.
BAAAAAH! Anyways I'm gettin real itchy so I fired up the engine yesterday.
As per the instruction booklet for my OS .46 FXi engine, I adjusted the throttle to idle without the engine stalling. Then I proceeed to let the engine idle for 5 secs and then bring the throttle wide open.
The engine hesitates almost stalls and take awhile to get to full throttle.
Again as per the booklet, this seems to mean that the mixture is too rich so I move the mixture control screw (which is the one with a spring on it next to the carb, right? not the needle vlave wich is behind the motor) 15 to 30% clockwise to see if it improves. I don't see any changes so
I keep doing this until I have the screw turned a whole 360% and still get the same results. No improvments. Am I doing this right and why does the engine sputter/hesitate/almost stall when I give full throttle.

Any help/tips would be greatly appreciated.

Keep going.

IF you are refering to the little screw on top of the carb that has a spring in it then no you are turning the wrong screw. Thats the throttle stop screw. The high end needle valve adjustment screw is the one on the back of the engine. If you were behind the plane and looking at the engine from there on the left hand side hanging out is a small hand adjustable screw and when you turn it, it clicks. Turning it out will richen and turning it in will lean it out. Make sure you follow the mfg recomendations for running the engine in on the ground. THe reason for doing so is not for just getting the motor started but for breaking in the engine. I am not sure if its a ringed engine or an ABC engine. I believe its ringed and the process of starting it on the ground at the settings they tell you is to seat the ring properly and so all of the parts meet the right way. Hope this helps

The screw with the spring on it is the throttle stop screw.The idle mixture screw is inside the barrel on the right hand side of the carb where the linkage hooks up. Look at the exploded views in your manual it labels all of the parts and screws and shows how they go together. Only turn the idle mixture (low end) screw a little at a time it is more sensitive than the high end needle.

buckskin has you on the right track. You sound like the idle mixture is too rich, which is safer for the engine than too lean of course. When adjusting the the idle mixture, turn CW to lean and only turn 1/8 turn at a time and test. Naturally shut down the engine during the adjustment due to the large meat slicer in front (propeller). Develop good safety habits now and they will reward you (and your fingers) in the future. After a few adjustments, re-tune the hi-speed and verify all is still OK. High end should be approx 3 clicks richer than peak. Your instructors will get into this more with you as your training progresses.

Come back to here if you have more questions. there will always be someone willing to help on any subject.

Welcome to the insanity. Just go ahead and drop off your wallet at the LHS.

First break it in. If you don't do that first then your adjustments are not going to be right: Start the engine, go to 3/4 throttle and using the high speed needle (the one on the back) figure out where the engine transistions from a 4 cycle sound to a 2 cycle sound. Once you find that run the engine just past that transition. You want a rich 2 cycle sound. Run for 2 minutes then let it completely cool. Repeat the cooling and running until you have gone though 2 takes of fuel.

Now that it's broke in you can start tuning. Work on full throttle running first, start with the large screw on the back and turn it in to lean it up until you hear the engine hit it's peak rpm then turn it back out 3-4 clicks. Once you have it running correctly with full throttle then work on your transfer. Move your throttle up and down, it shouldn't hesitate or bog when you go from idle to full throttle. If it does and you get a puff of smoke that means that your idle mixture is too rich, no smoke means it's too lean. As buckskin points out the idle mixture is the little tiny screw inside the carb barrel. Start turning it (inward if it's too rich, outward if it's too lean) 1/16th of a turn at a time (restarting your engine every time) until you can go from full to idle back to full without it bogging.

I spent an hour tuning my engine to perfection after deadsticking my plane once and it made all of the difference.

TOO windy???? The end of June??? Does this instructor fly his own planes in the wind ??? If he can take your plane off and then land it you should be flying it, you don't know how much you can learn in the wind and it all boils down to making you a better pilot. Besides he can help you get it set up right. Boy am I going to catch a rash for this post!!!

Good Luck and ENJOY!!! RED

red head,
You may catch a rash for this post, but you are completely right. Since I'm here in Oklahoma (the song was right. The wind really does come sweeping down the plains) flying in wind is something you have to learn. Luckily when I'm teaching students we don't have to wait for wind, it's an all the time thing. I see on here that some places consider 15 mph too much wind. That's a normal day for us. So my students always learn to fly in the wind. What's funny is watching some newer fliers at our field on the rare days that there is NO wind. It's so funny watching them. No matter how hard they try they always overshoot the runway without the wind to slow them down.

Ken

akschu- you are turning the idle screw in the wrong direction.

You were all right, I was turning the Idle Stop screw! I put it back to where it was originally. I will proceed to break-in the engine and then attemp to adjust the mixture control valve which is inside the throttle body. As suggested by buckskin I checked the parts layout and found it. Thanks to all who replied. I'm gonna give it a go tonight. As for the wind thing I don't know what to say except that I can't wait to get my plane up there!. You can only learn so much from a simualtor.

Thank you all for your help. This is a great forum.

Just to confuse you further, the "idle stop-screw" is really the "throttle-barrel retainer screw" & shouldn't be used for idle end-point settings -- use your throttle-linkage & radio throttle trims for idle settings.

britbrat- I don't have one in front of me and I don't have a steel memory so bear with me on this. Isn't there 2 screws on top? One w/o a spring that retains the barrel and the one with the spring for idle stop?

I honestly can't recall for sure but think I recall this.

Did some more digging:
http://www.osengines.com/parts/xr25681000.html

You can see they call it a rotor stop screw(idle stop). One screw, so I was wrong there. Screw does ALSO retain barrel in housng as it will come out if removed.

Still don't use for "idle" stop, use it for "KILL" stop

OK, thanks Bruce -- it does both functions. As we both said -- don't use it for idle setting.

Bruce, your right, I missed my mistake in the quick once over before posting. I have since fixed it.... thanks