I have a Twister with a GMS .32. Last year the engine had the rc carb on it, couldn't keep it running for more than a minute. Over the winter I decided to put a venturi  on it to see if that solved the problem. I found out today it didn't. Here is the setup Gms .32, evo venturi(smallest) Gms remote nva, os spraybar. I'm running a Brodak tank centered on the engine case. It doesn't seem to matter whether its on muffler pressure or not. I'm going to replace the GMS with an Os 40fp, because its my only plane set up for a stooge, but I'd like to get this setup to work. I have considered replacing the Gms rnva with a Brodak nva. It will run in a hard 2 cycle, then I back the needle off, to about 75%(rpm), by the time you get to the handle the RPMs are down, half way back to the plane it's stopped.
     Does this sound like an air leak? Thought I ask for advice before I tear into this.

Thanks
Steve
 
Ps  I'm running Byron 10% (20% oil i think) 

Are there any bubbles at all in the fuel line?  If so, there is a problem there.  It could be a fuel quality problem, too.

My GMS 76 would stop randomly when I put a small muffler on it. Went back to the big muffler and everything has been fine since.

Also consider air leaks at the remove NVA and the front bearing.... GMS favourites.

Try a different fuel with at least 20%-23% synthetic/castor oil. Byron fuel with an unknown oil quantity is asking for trouble. Sounds like you're over heating from low oil content.

     I think trying a different fuel is a good idea, but I ran Byron fuel for quite a while, and tested the content, and the 20% oil fuel was about 20%, and the 16% oil fuel was 16%, at least to the accuracy of my test. It also ran *much* smoother than any other fuel, and also was about the only fuel that wouldn't give me the occasional flame-out on several types of engines. It was weak for its stated nitro content and it was rather expensive, but otherwise, it worked very well for me.

      Brett

May have found the issue. The fuel line from the tank to the rnva had a hole in it. Still swapped the rnva for a brodak nva. Hope to at least run the engine at the field today, if the weather cooperates.

Steve

If this is like a ST needle, with the jamb nut on the end then carefully snugging the jamb down some more shoul provide enough friction ti keep it in place. If everything elae is ok you should'nt need anything to keep it in place.

An FYI:  I have gone to using the PA NVAs because they have the nylon (or something! LOL!!) insert in the "locking nut".  This eliminates any air leaks and eliminates the needle working loose.  Finger tight, or a touch more, is all that is needed to keep the needle in place.  They really ARE the best NVAs for our use.

Big Bear