Do I have an air leak?
 

I have a 50sx. It seams to have been run lean a couple of times because i noticed the oil from my Cool power 15% to be a darker cooler than normal. I watched the line from the remote needle to the carb the other day and saw air entering. I'm about 3 1/2 turns out @ 40F and 500 PA. I'm new to airplanes and have set the needles and pointed the airplane up at high RPM to check the mixture. No drop or increase in RPM. But when I landed, I noticed the oil color. Running a 12x7 Prop on Sig LT-40.

Any input would be appreciated.

RE: Do I have an air leak?
 

If there are air bubbles in the line going to the carb, yes, you have an air leak. 3 1/2 turns open... very wide open for any temp/pressure. You don't say how long you've been flying this airplane, but hair splits in fuel lines is a fairly common occurence. I would replace the line from the valve to the carb, run it and see if your bubbles are gone. It's also possible that the "O" Ring in the needle valve is worn and allowing air to enter.
As far as the darker oil color, it could be any number of things, but one I'd check first is that the hardware holding your muffler together is tight.

Andy

RE: Do I have an air leak?
 

You can also use teflon tape around the needle threads. I've seen that work perfect many times on engines that have air leaks.

RE: Do I have an air leak?
 

Thanks! That will start me in the right direction. The motor has 1 gallon of cool power 15% through it. I'm encouraged that the color of the oil could be caused by a loose muffler. I found it loose last night I was told by a couple people that it was metal from overheating my engine. I found that the screw and nut on the front and back of the pipe needed to be tightened. That screw was sure corroded when I pulled it from the pipe. Also, I replaced the tubing from the stopper to the clunk. It's thicker tubing though. Sounds like I should replace it all just to be safe.

RE: Do I have an air leak?
 

There was a thread not long ago about a remote needle OS that was having a problem with air in the line. After much diagnosis, new lines, etc, the owner finally discovered a crack in the needle assembly. If I recall correctly, he called OS service and they sent him a new one free.