I have an Evolution .46 engine in my newly purchased trainer kit. The engine runs great at and above half throttle but will die at any rpm setting below half after a couple of seconds. My high and low speed needles have stops so that I can't turn either of them too far and I have set both of them at every possible combination of settings and still can not get this thing to idle. Can someone please tell me what I'm doing wrong?

Thanks,

First thing I would check is to make sure the carb is not closing off. Look in the intake make sure the barrel is not closed off when you retart the throttle below 1/2. The throttle linkage may need adjusting. If that's ok it sounds as though the idle mixture is too lean or to rich.....does the engine smoke alot and have fuel coming from the exhaust before it dies? if so to rich. If it suddenly quits to lean. Follw instructions from OEM to correct.

It tooks something close to 6 month for me to get my evo 46 working, I mean, I guess it is working, since I left it last night.
I also couldn't ajust it within the limits it came from factory. In fact, even after removing the stops and playing all possible, it didn't work, so I sent it back to the dam Horizon and they said they replaced the carb.
Got it back from then and thought it was good, but after couple attempts to fly, there again some problems.
I just got from Mike (minnflyer) some reference where the low speed needle should be and tried last night to adust like that, but again the adjust where I could consider it acceptable is quite lean than what should be.
Will try this weekend and see if it still works good, since it seems to have a random behavior.

What should be is like this:

1) Firts set your throttle to idle and the trim to 50%. Then adjust the throttle linkage to make the carb barrel open 1mm = penny thikness.
2)With this on place remove the idle needle stops by removing an alen screw at the blue colar. You have to remove this blue colar. Inside it will be located the idle needle screw.
3)Turn the screw(needle) clockwise until you close the needle(don't put much strengh to avoid damage the needle)
4)Open the screw counter clockwise 1 1/5 turns ( about 360 + 70 degrees). This should be the correct position and the center of adjustment allowed by the stops later when you put it back.
5)Start the engine and try to see what happen. If the idle is bad, try to adjust the idle needle around the 1 1/5 turns to get a god idle, but not much far from it.Adjust the high speed needle as the max rpm and turn counter clockwise a bit with small decrease in rpm(rich side).
6)Let it idle and you may need to adjust the idle again.
7)You also can check the idle needle by the pinch test, that consist on pinching the fuel line when idle and the rpm should increase a bit. If it increases a lot, it is too rich. If it just dies, it is too lean. If is rich, close the idle needle(clockwise). If is too lean, open the needle(couter clockwise).
8)If all works good, put back the stop and let it be in the center of possible adjust.

Like I said, my idle need position where it worked was 3/4 turns from closed and not 1 1/5.

Good luck.

Nilo

I had problems helping some new guys at the club with these engines. Every one was fixed with a glow plug with a idle bar. None of the factory ones had them? Does yours?

The only thing would say differently from what Nilo said is:

#5 start the engine, but get the HIGH END running properly using the high end needle valve. Then the idle should be right.

Thanks for the advice and tips. After reading your suggestions, I did take the adjustment needles' stops completely off and got it to run perfectly. I was a little afraid at first in doing this with the manufacturer stressing the importance of not overleaning the engine.

Overall, the plane flew well, the engine performed great and I am very pleased with my accomplishments.

Thanks again for all of your help!