I have a Hobbico Twinstar that is running two OS .40la engines. Both of the engines are brand new. One of the engines runs fine, but the other engine will run only at full throttle. If I close the throttle the carburator does close, but the engine will still run full throttle. Eventually the engine does start to slow down, but then it begins to speed up and then slow down over and over again. Some guys at my local field took a look at it. We saw some air bubbles running in the fuel line (not many at all). We checked over the fuel tank and all of it's lines but found no leaks. We found that the needle valve was touching the nacelle, so I trimmed the nacelle so that the needle valve was no longer touching anything. Still had the same problem after that. The other engine is running flawlessly. Both engines when at full throttle synch up well, but when the throttle is brought back one engine will come back to a nice idle while the other one stays at full-3/4 throttle and then speed up and slow down over and over again. Any suggestions???

Thanks
HighGs