What little experience at engine tuning I have has been learned right here in RCU from these guys and have gotten to the point where I can tune my engines to run well, fast & reliable with good transition from idle to full throttle. I don't believe however that the riding to close to the wood has anything to do with your problem. I took the stock muffler off of my OS .46 FXI in my NexStar & mounted a tuned pipe that came with a TS .56 that I had with a pitts style muffler on it. Britbrat had told me the FXI really liked this type of tuned pipe so I had this new one just sitting there and luckily the bolt pattern is the same from the .56 to the .46. However it doesn't stick as far out as the stock muffler did. It rides right along the side of the wood fuse, where as the stock muffler had at least 3/8 in clearance between the muffler & the fuse and it made know difference at all except a huge increase in power from the .46FXI, just as Britbrat had told me it would. It has been mounted this way for a few months now & is more powerfull & reliable than ever. Without a single dead-stick to it's name. I believe your answer was stated above in either DMcQinn, chashint, or darock's post. but I wouldn't get to carving on the fuse just yet. I think it's just a matter of one or more of the above listed scenarios. Either tank too high, or engine tuned too lean, or leak somewhere in fuel lines or a combination of the three.

This is the type of pipe I changed the .46FXI too. While it is not the .46 AX it has been pointed out to me that the same updates that were done to make the .46 AX have also been done to the .46 FXI resulting in the same type of power out put. I've seen it for myself in performance as my flying partner gets mad as &*$% when we break out the Trainers & My NeXstar laps his Sky Raider with the .46 AX with the stock pipe on it.[sm=lol.gif] Especially since the price for the .46AX is quite a bit more. The pipe is very similar to the one that comes stock on my Tower .46 PRO, which by the way will also outrun his AX.


http://www2.towerhobbies.com/cgi-bin...?&I=LXJB16&P=0


That pipe made all the difference in the world for my OS .46 FXI and as I said it literally rides right along side the fuse no moe than 1/32 clearance between the two if that, as in I might be able to slide a few sheets of paper between them but that's about it and it doesn't burn the covering on the fuse & it certainly doesn't effect the performance of the eninge except in a 100% positive way. IMO you should just break out the manual from your TT .46 PRO & re-read their tuning procedure as well as looking at some previous engine tuning threads here on RCU & you will get it dialed in without having to hack away at your fuse. I had a recent problem trying to get my TS .56 running right, dead-sticking an such eventually while the experienced person at the club who was trying to help me did find a fuel line leak (sucking air) he got the thing so out of whack tuning wise after we re-placed all the fuel lines to new, that it wouldn't even start anymore. He was so frustrated with it at that time he stated I'm done with it there is something seriously wrong with that engine!! As he walked away back to his planes I got out the manual set both high & low end needles to the original factory settings. It fired right up, he turned around & gave me this look [&:] then I started tuning per tuning techniques learned in here, & in just a few minutes had the high end adjusted for peak performace then backed it off about 1/4 turn for a thin stream of blue smoke. Then adjusted & leaned the low end till I had a perfect smoothe transition. By this time he was just standing there with his arms crossed and giving me that same look again. So I asked him if he would pick the plane up for me so I could re-check the high end after setting the low end. I had him point it straight up while at full throttle after a few seconds it sputtered & died, still a little too lean, I fattened it up another 1/4 turn & tried it again. It just kept on screaming at full throttle pointed staright up, had him put it back on the ground & let it idle then stabbed the throttle. Still had perfect transition wa-lah! Houston we have ignition. He then asked where I learned to do that & stated "see if I ever try to help you anymore, you don't need me" ( in a friendly way though). So I told him I learned that from an engine tuning thread on that website called RCU that you guys allways roll your eyes & scoff at everytime I mention it. LOL[sm=lol.gif]