I took out my trainer today with a OS .46ax with a 11-6 prop and was flying around just fine. I throttle back to 1/4 to do some slow flight. After a couple of circles around the pattern i throttled up to pick up speed. It sputtered and the engine died. I dead sticked it in ok. I started the engine back up and noticed that at 1/4 throttle(5000 rpm) the engine sorta boggs down and sounds rough. I could not get it to die again but it just is running odd. I idles ok at 3400rpm and revs to a max of 12400rpm. Is there some kind of midrange adjustment that can help?

skeeter

3400? you should be shooting for about 2100. turn it down to this level then adjust your low speed needle it is proabably way too rich.

how far are your needle valves turned out from being all the way in. the two needle valves work together to give a good idle and power but if the are not set right you can get it running good in certain rpms and bad in others. the best way to solve the problem is set both needles back to factory recommended position and then adjust from there otherwise you will be chasing good running spots all over the settings and never get a good overall running engine

what Jeffie said.

So where can i find the original needle settings? I no longer have the original papers that came with the engine.

skeeter

I'm not sure you need the original settings. Start by adjusting the high-speed needle valve to where you'd want it at full throttle. Then, go to idle and adjust the low-speed valve. If, as seems likely, this leads to making the low-speed setting leaner, go back to full throttle and you should find that you have to make that a little richer. Etc.

Hey,
These guys pretty much nailed it. Go to Towerhobby.com and you can look up the motor and download the manual. From your description your low end is like just a skosh rich so loading up at low RPMs. Remember that the low end adjustments SHOULD be very very small and you are fairly close so try just a turn towards lean about the same distance as the width of the slot on the screw. Being patient will get you there quicker than anything. it may take several attempts to DIAL IT IN. Once set correctly it stays that way( if break in is complete)for the most part you will only have to tweak the high end a click or two for humidity etc.

Like he said, as it breaks in you will have to make minor adjustments to both needles to get it perfect. This is commonly overlooked.

skeeter I just did this a little bit ago after a crash I replaced some parts and coudn't find my manual if you go to tower there is the manual to download if you like.

the basic set up to start from if you get lost while setting the needles up is.
close the throttle so the barrel just barely covers the opening, screw the low speed needle until it stops, dont force it,the back the screw out 3/4 turn, this is the basic position for the LSN from there you can adjust it to run for your engine, asmall tweak here or there and you will find the perfect position, mine ran pretty well after setting it there, I may do some fine adjustment later since it seemed a little lean on the low end but not enough to go nuts about.

I flew it the next weekend, and it ran better than before, with none of the bog it had before I crashed, the settigns were from when I took it out of the box new so it was a little rich for break in, of course I found the book after the flying day was over.