Hi all
I recently bought a .46 AX and everytime I fly with it, it results in a two minute flight and a deadstick...after that kept going on for about 10 flights, I came to my senses and said, "Theres something wrong." Turns out the fuel line in the tank was leaking...well, after replacing the fuel lines, now I have a mixture problem, I think. While testing the engine, it throttles up nicely, but it hates to idle...it only idles for like 30 seconds before shutting down. Sometimes, it idles nicely then randomly shuts down, while other times it sounds like its revving too fast and it shuts down. This is with the needles exactly the same. The engine is in a Avistar and burning Omega 10% fuel and a O.S. A3 glow plug....can someone please enlighten me on what (probably obvious) mistake I'm doing?

Thanks

I have 4 of them in 2 twins and they are great little engines. Once adjusted, they need very little changing. I have 11-5 APC props on mine right now.

Sounds like you have a low end mixture problem.

Start your engine, idle it down leaving the battery on. Pinch off the fuel line and listen. If the engine quits fairly quickly, your low end is too lean, open it up a quarter turn and try this.

If your engine runs for a few seconds, then speeds up a good bit, it is too rich. Turn the idle mixture in a quarter turn and try.

It should speed up slightly, then die.

As for the top end, peak it out, then open it up 3-4 clicks. You should have a nice smoke trail for the first couple of minutes of the flight. The engine leans out as the fuel burns down, so you need to set slightly rich at first. If you want to peak the engine, only fill the tank a quarter full, then peak the engine. Fill the tank completely, but don't touch the needle.

After the engine is set, you shouldn't have to change the needle unless you have a really humid day, especially a foggy day. High humidity will give you a rich run. Lean it out a few clicks, but don't touch the low end. You'll have to re-do it when the weather dries out.

k thanks...uhh...where is the LSN? I can't seem to find it...theres no screw sticking out of the carb...

I just tested it...it took about 15 seconds to die out...it sped up a little bit, but not much. That was with me about to cut the fuel line with my fingernail pinching it.

The dead sticking at high power settings could be a lean setting of the high-speed needle. The high speed needle should be leaned out at full throttle until the enging "peaks", then backed-off (richened) until you just hear a small drop in RPM.

Conversely, at idle, it sounds like the low speed setting is rich -- the cranckcase is loading up with fuel & eventually the engine floods out.

The high-speed needle must be correctly set before you start adjusting the low speed needle. The LSN is adjusted by turning the screw inside the center of the throttle arm assembly, located on the right side of the carb --- look in the end of the throttle barrel & you will see it. Make adjustments in 1/8 - 1/4 turn increments. Turning it clockwise leans the low speed mixture & turning it anti-clockwise richens it.


Once you have the low speed needle adjusted satisfactorily, the engine will idle reliably for an extended period & accelerate to full power without stumbling or stopping.

thank you for the reply, I'll test that today. [sm=thumbup.gif]

The low speed needle in recessed in a hole on the side of the carb opposite where the fuel line hooks up. You'll need a small screw driver to reach in there. 15 seconds to quit sounds like you are too righ at idle. You need to get a small, flat, screw driver and turn this screw in, clockwise a quarter turn.

Open the top end up a quarter turn. Any time you quit up in the air at full power, it is usually either running too lean or a fuel line/tank problem.

hold off on the quarter turn on the low speed needle valve. That is way too much to be adjusting that screw in one shot turn the screw in little increments of about 1/16 to 1/8 or you will be chasing the setting and don't have the engine running while doing this or you could get a cut hand on the prop.

The low speed needle adjustment is a pain to do but once set, it will make all the difference in the world. It also helps tremendously with the transition between mid-range, where most of us operate the engine while in flight. We don't usually run wide open throttle for the entire tank of fuel, you probably run half throttle most of the time so this adjustment, once right, it really improves this mid range run as well as the idle and transition from low to high speed.

DS.

Thank y'all for helping. So far, I can't find a screw driver small enough to fit in there [:@] but when I do, I'm sure I can get the engine running right.

So far, this is how the engine problem is going...

I got a screwdriver that can turn the LSN.
When I started it up, I maxed out the HSN, backed out 3 clicks, and let it idle (with battery on)
I turned the LSN about 1/8 of a turn richer...then, I removed the battery. It shut off imediately. Then, I returned the LSN screw to where it was (factory position) and started up. Removed the battery and off goes the engine imediatly. Leaner 1/8 of a turn and same. Leaner/richer 1/16 of a turn and same. Then, while idleing for the second w/o the battery on one start up, the spinner explodes in to two pieces, near the propeller. Before starting up, I did a pre-flight even though it was in my backyard for testing which included checking the spinner for hairline cracks or any defects and testing the tightness of the prop nut. Now, I'm down and out without a airplane to fly for tomorrow seeing as my brushless E-Flite needs more parts and my US 60 needs a different servo. And, the LHS closes in 2 1/2 hours and I can't get a ride in time. Can anyone help with my mixture problem? The LSN is in the factory position and I'm burning Omega 10%.

I'm not going to comment on the adjustments, I think people play with the low speed to soon and to often, my opinion!! I will comment on the blown spinner. Always make sure that NONE of the prop touches the cut outs on the spinner. If it does that can cause spinner problems.
ENJOY 111 RED

I was sure of that (not touching the prop part)...I found a spare spinner in the workshop...and micro hardware and a servo...looks like I'll be flyin' tomorrow!

Great flying today...my instructor (more or less just advisior) tuned my AX and now it purrs good. So, I went up with the Avistar, and flew around...no dead sticks! Then, my advisor said that I was missing a wheel on the landing gear (the mains, its a taildragger) So, I bring it in for approach, and come in so slow, I can practically walk faster than it...so then, the airplane does a perfect 3 pointer and stops in about 3 feet. So, with the Avistar missing a wheel on the mains, I go fly the US 60, which hasn't seen sky for 6 months. The stabs were all dusty just sitting there for so long. [X(] So, I flip start it, starts on the 3rd flip, and retune it, and go flying. With both the Avistar and the US 60, I need about 1/4 throttle to maintain straight and level flight at a comfortable speed...I can pull vertical with both airplanes at full power...the US 60 is powered by a OS MAX .61 FX. Anyway, I snap roll it and fly upside down and do immelmens (sp?) with it...so, comming in to land, I bounce once near the beginning of the runway, maintain about 5 feet of altitude for about half the runway, then do a perfect 3 point landing. Now, time to fly the electric E-Flite Tribute...I snap roll it left and right, hover it, knive edge it, torque roll it, and stuff, then I was getting into an approach to land like with a nitro airplane, and then my advisor said I can just fly it to the runway and kill the motor and glide down...no need for an approach...I knew that! . At the request of my older sister (who drove me to the flying field) and my advisor, I flew the US 60 one more time.

to prevent loss of wheels I put a piece of fuel tubing on the outside of the axle. It holds the collett or nut on for one emergency

If you put a very thin slice of fuel hose between the wheel(mains) and the wheel collar, it can also help slow a plane after it contacts runway,,,perhaps this will help if you have long roll outs later.

Here's a diagram of what Sooner Ace is talking about. This does a great job of slowing your plane down.

Ken

k thanks guys!

What would that do on say an H9 P-51? I have an aweful time with it continuing to roll out at fast speeds after landing. My guess it would cause it to nose over quite easily?

Shakes, spoilerons

Shakes: I've used that on tail draggers , you just have to adjust it so it JUST touches. As the plane rolls the tube sort of expands ( very little ) and slows the plane. Too tight, FLIP job!!! ( on tail draggers, no problem on trikes. ) ENJOY !!!! RED