Ok, so I ran a tank of gas through the O.S. 46 fx as the instructions said, varying the mixture. But I had a ton of bubbles coming through the fuel lines. Changed out the prop for a better balanced one and that eliminated about 2/3 of the bubbles. I'm still getting some but not enough to cause it to sputter like before.
My current problem is that the when you take the engine from idle to full power it bogs down and takes 2 or 3 sec. to rev up. Is this normal? I wouldn't think so. I'm concerned, I'm supposed to take my first flights this weekend and I don't want to get in the air the first time and have a dead stick, Any ideas.
I am running cool power 15% nitro.
Thanks

Sounds like it's rich on the low end. I'd really recommend fuel with a bit of castor in it, at least until you're more familiar with tuning. I like Sig 10% 2-stroke fuel for my two strokes, but I realize some are kinda religious about not running castor. I'd rather clean my planes than rebuild engines, just my two cents worth.

Do you think that 15% NITRO is too much for this engine? I basically no nothing about nitro fuel.

Not too much, just more than necessary. I've tried both and find that I couldn't really tell a significant difference between them in OS engines. I'd go with the lower cost of the 10%. The castor thing is more important, it gives you additional protection against inadvertant lean runs. I run 15% nitro in my 4-strokes, but I still run Omega fuel, it has about 5% castor in it. Might make my muffler dark, but I can deal with that!

15% will make the engine run a little hotter, but will help it idle a bit better. You will also burn more fuel as you go up in nitro content.

By the way, the primary "benefit" of increased nitro is supposed to be better performance, but the difference in RPM between 10% and 15% is usually about 300. Hardly worth the extra cost and engine wear when you can get a similar performance boost by using a spinner or balancing the prop.

Your engine's low end definitley sounds a bit rich. There should be a very small screw inside the throttle arm of the FX, which is the low end adjustment. Turn it in (clockwise) about a 1/4 turn and see if it makes a difference. It should make the transition better. If it does, you can try adjusting it a bit more until the hesitation goes away.

Once you get rid of the hesitation, you'll probably have to re-adjust the high end, because one affects the other a bit.

Good luck with your first flight this weekend!

By the way, your instructor will most likely fine tune the engine anyway, so don't be too concerned.
Dennis-

Wall,
Try turning the low end needle clockwise an 1/8 of a turn, testing the throttle response and keep turning it clockwise until the response is better. If the engine cuts out immediately when you throttle up, turn the needle back a little.
GLflyer

You do not really need 15% nitro , 10% will be fine for most Trainer-Sport aircraft. Check your fuel lines for punctures (or small holes). Have an experienced pilot check your plane and DO NOT attempt to fly on your own! Get the help of a certified instructor or an experienced modeler. Good luck.

Thanks guys, I really do appreciate it.
Yep, I've been praticing on G2 sim for a while and I have scale flight experience, so I at least understand the principals of flight. But I've got an instructor lined up. I've got to admit that I would love to go out to the field when no one else was there and give it a shot by myself for the first time. but I'm not willing to risk my plane on it. I've waited since I was a kid for this thing and want to do it right.
Just as a side note, these forums are great. I'm the kind of person that wants to get his hands on all the info possible then I get into something new and I've deffenitely found it here. I spend a couple hours every night just reading old posts trying to gain as much knowledge as possible.
Thanks again,