i havent a clue whats wrong i keep tunning it when it starts but when its in the air for a few mins it just cuts out sounds like its not getting enough fuel but im not sure. please help????

Check for holes in your fuel lines. Had the same problem with a .46LA and appeared to be a very very small hole in the fuel ine right after the tank exit.

Also, check if the clunk inside the tank isn't flipped forward.

If it works for a few minutes before going out, it's not a fuel line outside of the tank. Could have something to do with the tank assembly. Make sure it's put together right with new fuel lines.

Sounds like it's just not adjusted properly. It is more than likely running too lean...Ask an experienced flyer at your club to help you adjust it. When you lean it out for peak RPM, back it up (rich/counterclockwise) until you hear a noticable drop in RPM. Always run it on te rich side...

check for lean running. When it runs lean, it gets real hot...real fast and looses a lot of power. Had the same problem for a while with a .70 surpass 4-stroke in a cowl. It would get really hot and start to cut out until I cut out a lot of the cowl.

Sounds lean to me too.

Engines lean a bit further once they're in the air. (Engine load is less.) so you do need to keep it one the rich side.
Dennis-

i had this same exact problem. if your engine is new , just keep flying it the way it is . That is the way it breaks in (loses power after about 5 min) After about 10, 15 flights it will be strong through out the whole flight. And it will be broken in fully.

Breaking in isn't the problem. I am having this same problem with 3 new OS engines. The needle valve is leaking air for some reason. They sell an O ring for the needle valve that is 6.5 MM but it is like $13 for 2. Freekin rip off. I emailed the OS rep about the problem and he didn't have the decency or courtesy to even drop a note back. There are a lot of OS engines having this problem. I am going to find an O ring and try it, if it doesn't work, I am dumping all my newer OS engines and going to a different brand. this rear needle sucks! They know they have a problem and they refuse to deal with it. I am so frusterated with OS I can't believe it. used to be a great engine. Boneheads had to screw up a good thing and move the needle so some dumb ***** didn't get his fingers in the prop. What a crock.

you need to start with adjusting the low end, ,ake sure the throttle is fully closed and stick a t pin in the air bleed hloe in the front of the card then turn the low speed adjustment in till it touches the t pin, start the engine set the idle a little high and pinch the fuel line it should pick up speed when you do. then open the throttle wide open and set the high speed needle by listening to the engine i do this by getting a good high speed sound the pinch the line it slhould pick up if it dosent its too lean turn it out about an 1/8 turn and repeat till it picks up hope this helps, if your not comfortable with this get an experienced pilot to set it up for ya dont butn your engine up the os la is an great engine and should last ya a while if you dont burn it up runnign it lean rickey

Try checking your fuel tank. I had the same exact problem and found out that fuel tank was vibrating like hell inside the fuselage causing abnormal delivery of fuel. Start the engine with the wing off(make sure you cover your electronics with a piece of cloth) and check the tank.Give full throttle and adjust the needle valve as you would normally do. If you can see fuel foaming inside the tank or the tank vibrating then try to cover it with foam or anything to reduce vibration.

I agree with those saying it is running lean and getting hot......if it gets too hot that engine will stop right now.....

Flyboy, switch to Thunder Tiger Pro engines......I love 'em. My main problems with OS engines has been the mufflers leaking at the seam between the front and back.....I've had to take them apart and RTV the seam in both OS's that I have.

I've had the screw that tightens the tank assembly, in the middle of the front of the tank, come loose, so that when you were flying around and at about half-a tank, there would be an air leak, and the engine would obviously die. Just something to check.