I am new to Nitro planes. I have bought a Nextstar from Hobbico. Is it normal for Fuel to come out of the Muffler. And if I was to take the Baffle out of the muffler will it do any damage to the motor?
Please Help me. Dont want to ruin anything before I get to fly it.
I am using a 13% nitro fuel and running an O.S .46FX Motor.

It's entirely normal to lose fuel out of the muffler. The pressure tap line leads back into the tank, when you over fill the tank it will flow out the muffler. There's no benefit to be gained by removing the baffle from the muffler, just makes more noise, something our flying field neighbors can do without.

You will also have less back pressure which will result in lower mufler pressure to the tank which will result in leaner engine runs so you'll have to richen your mixture and use more fuel etc etc.

Most agree its best to leave the baffle in place.

Hmm, was wondering what kind of fuel you are using because never heard of 13% nito fuel?? Check the oil content, it must say that it contains at least 18% oil or your engine will not be protected. Since you are starting out and want to use this engine foe training, just leave the baffle in. The engine will be easier to adjust for reliable running and it will run quieter. Btw, a fuel with 10% nitro content is all you really need for most applications. Just for info what prop are you using?

Big D-

I agree that you don't want to ruin anything before you fly it. Your questions give me some concern that 1) You may be trying to start the engine in a "hydro-locked" condition with too much fuel in the combustion chamber and 2) you may not know for certain how to break an engine in. Either of those two things could lead you to seriously damage your motor. I recommend that you either try to hook up with someone with more experience for breaking in your engine or ask some more questions if you are unsure of what to do. Believe me, I know the feeling of wanting to see your first engine run.

-Scott

As others have said, leave the baffle in there for now. You will pick up more power if you take it out later, but at the expense of making the engine a little harder to set (the OS engines actually generally respond pretty well to the baffle coming out, they don't get really finiky like some engines do). But the main point is that at this stage, you don't need the extra power anyway, so leave the baffle in there. Later one, after you've been flying for a while, and know how to run engines, you can start expiermenting with doing basic engine mods to get more power. Walk first, then run .

It's not clear to me if the fuel coming out of the muffler you are talking abotu is when you are trying to start the engine, or after it's running already. If you have fuel coming out while you are running, that's not a huge deal, it just means your needle valve is too rich. Lean out the mixture a little, and the raw fuel will go away. However, you will always get oil coming out. If you don't have oil in the exhaust, you're running way way too lean, and you're cooking off your engine.

The 13% nitro thing worries me, as does you referring to the plans as "nitro planes", a term that is common with car folk, but the plane community usually referrs to these kinds of planes as "glow" as opposed to "spark". (after all, you can run 0% nitro if you want, though I wouldn't unless you have a reason to (leaving out the reasons for the moemnt)).

Anyway, my point about the car reference is this: don't run car fuel in your airplane. Airplane engines need more oil.

I agree with the advice above that for sport flying 10-15% nitro is about right for most flying. Most guys can't tell 10% from 15% with out using a tach, so save your money and go with 10%.

Leave the baffle in and make sure the exhaust nipple is pointing down