Ok I have a os .46 FX that i pulled out of one plane and installed in another. The engine ran perfect. However when i installed it in the new plane. When i hold the plane vertical, it will run for about 3 seconds then fuel just starts pouring out of the muffler and it dies. And yeah, its quit a bit of fuel coming out of the muffler, not just a little.
The engine is not quit mounted inverted, its between horizontally and inverted mounted.

Whats wrong.

Fuel level, you are flooding out the engine. The fuel tank is to high in relation to Carb jet. You need to lower it. Also you are probably syphoning fuel before the engine is even started. It makes no differance whether the engine is mounted upside down, 45 down, sideways or upright the fuel tank will still need to be in the same vertical relationship with the Carb as it was in an upright position.


John

Are you saying the engine runs OK when sitting on it's landing gear but when you pick it up and hold it nose high that the fuel starts running out of the muffler? If this is correct, do you run the engine up to high RPM before you lift the nose to give the engine a chance to blow accumulated fuel out of the muffler? What would happen if you had someone hold the plane in such a way that the motor was in a "normal" attitude and then lifted the nose? This might also give you a clue. Do you have a good reason for this mounting position?

yes i ran the engine at full throttle and then sitting on its gear and everythings fine. Then when i hold it verticle with the engine still at full throttle it only stays running for about three seconds and then pretty much acts like it floods itself with all that fuel running out. It struggles looses RPM and then dies.

Just a thought...

Make sure that you have not accidentally switched the connections between the pressure line and the fuel line on the fuel tank. I'm assuming you have a two line setup.

With the engine canted and the muffler hanging low, it is a good recipe for siponing back from the tank especially if it was drawing of the fuel line. The muffler is probably large enough to hold quite a bit of fuel and when you tip it up it may dump out quite a lot.

As far as the quitting after 3 seconds goes, the symptoms you describe sound like flooding which is curious. However if the engine RPMs raise for a few seconds and then slow to a quit, it is probably a leaning issue. Again if the lines were switched it would probably suck air when tilted and starve for fuel (lean) and quit, which is similar to what you describe.

You might also check that your pressure line inside the tank curves up almost to the 'roof' of the fuel tank. If you accidentally mounted the tank upside down it may not pressurize well and may also cause the symptoms you describe.

Are you running a click or 2 on the rich side of peak before lifting the nose? Does the engine pick up RPM briefly before dieing? [sm=confused.gif] Can you mock up/simulate this installation on an engine stand out of the airplane? Reproduce ALL conditions, such as tank height and engine angle and use as many components as you can from the plane. You might try building the stand on a pivoting board. Could be internal tank problem.

Lower the fuel tank. If you change to inverted, 45 down or even sideways if you fail to maintain the same fuel tank to carb relationship it always results in syphoning and these problems.

Pretty sure the tank will be lower when the nose is pointed straight up. Engine runs OK he said with plane on wheels. See post #4.

Bruce what is happening is the engine is thoughly loaded before it is started and its being needled lean to correct or the midrange is already excessively lean then when tilted it dumps out the remaing muffler load and proceeds to quit lean.

Lower the fuel tank to a resonable carb/tank relationship and the problem will subside.

John

As always just an opinion

Ok guys, thanks for all the imput. Heres the last part that i forgot to list. My fault. Ok i Actually flew the plane for about 5 minutes in sharp turns and figure eights. But it died as soon as i tried to fly vertical.

As for running it on the ground, it runs great(untill i hold it vertical). I mean i had this exact engine in a ultrastick and there were NO issues ever.

John, do you think his clunk is at the front of the tank? Or maybe a hole in the pickup line inside the tank? NEED to check your tank out NOW!!

Yup Bruce the story is changing a little and now its sounding like simple leanout cause by all the usual reasons airleaks, a pinched clunk line like you said or blocked agingst the back of the tank or just too aggressive on the needle.

John

Troubleshooting is always hard to do from hundreds of miles away, especially without ALL of the info.

Time for me to go fly. Ya'll have a good weekend. See you Monday.