Kostas1

Guys,
i recently bought a used OS 40LA,
and today i fired it up.

I used an APC 11x6 prop,
10% N Cool power fuel.

My problem is that when i put my airplane vertical by hand to try and see if the engine stalls,
it actually did.

No matter how much i opened the high speed needle valve,
from 2 turns to 3-1/2 from fully closed.

Also,
the engine came without the needle holder,
but because i wanted to try it TODAY
i glued a piece of wood on the firewall and installed the needle valve there,with a self taping srew.

Also,
i saw that the needle valve is approximately 5 fingers higher than the carb position.
Does that affect the engine?

Last,
idle is perfect,also the WOT and transition.
But when i grab the ARF and put it in vertical position,
it runs and then stalls.[:@]

dalolyn

My Feedback: (7)

do you have your fuel tank hooked up to the pressure tap on the muffler.

earlwb

In my experiences a 11x6 prop may be too big for the engine. I run a 10x6 prop on them Ok.
You might be loading it down too much.
The engines are not a powerhouse. They were designed as a entry level engine that is easy to use and run.
if the prop is too large, it loads the engine down a lot, and the engine doesn't draw fuel at the lower RPMs very well.

Did you hook up the muffler and run the fuel tank vent tube to the vent fitting on the muffler?
 A little muffler pressure is good for the fuel draw.
Sometimes the fitting has the hole in it blocked, it's worth it to poke a paper clip end or something down it to see if it is blocked or not and clear it out.
Also try to keep the fuel lines going to the carb as short as possible.
You don't see any air bubbles in the fuel lines do you? Especially the short fuel line from the remote needle to the carb.
What size fuel tubing are you using? Small, medium, large or extra large. I think medium is the one to use on the engine.

pe reivers

prop is too large for a new LA engine. A 10x6 is plenty prop for any .40, especialy when running in.

Kostas1

Guys,
the engine is used,not new,

and according to the owner it is also run in.

Using the APC 11x6 i get a good "slow" idle,
even at full throttle,
with the nose at the usual position,engine works fine,

Only problem is when i put the plane verical.

I have the 3-line setup on the fuel tank.
One for filling,
one for the muffler,
one for the needle valve[]

djlyon

Hopefully you have the filling one plugged when you are running the engine. If you don't the one to the muffler isn't doing you any good.

Denis

tigrejohn

My Feedback: (7)

Many variables can cause the problem the problem you have: WOT set too lean; fuel tank position too high; wrong heat range glow plug; insufficient muffler pressure to fuel tank.

Set WOT with a slow pinch test on the fuel line. If set correctly, you should hear a slight increase in RPM's. If set too rich, you will hear a larger RPM increase. If set too lean, you will get a drop in RPM or the engine will die.

Tank position: the centerline of the tank should between in line with the spraybar to 10mm below it. Your positioning of your needle valve should not have an effect. Commonly, people run into the problem of a too high tank if they mount their motor sideways or inverted on an airframe designed for an upright engine and not reposition the tank.

As for the glow plug, you need a hot heat range plug like the OS #8. A colder plug can give you "flame outs" and not show it on the ground.

Check the pressure nipple on the muffler for plugging or constriction and your tubing for a leak. Well used mufflers will get a buildup of varnish or gunk. Remove the nipple, clean off the face and run a drill or wire through it to clean out the hole.

Other than that, my only other recommendation is change your propeller to a 10x5 or 10x6. An 11x6 is too much load for that motor.

TFF

Way to big a prop for a LA40. If it goes lean it could be overheating and stopping. My son's trainer has a 10x6 on one and has a low idle. On a ww1 fokker D8 I ran an FP40 with an 11x4. That prop needs to be on a .46AX.

huck1199

I agree with all that has been said; all those variables apply. What strikes me is you said the needle valve is 5 fingers above the carb. Does your fuel have to travel uphill 4"? Seems quite a big distance.

fredscz

My Feedback: (47)

One more thing that you should check is to make sure the clunk is not up against the back of the tank. If it is against the back of the tank it can shut off the fuel real quick. I try to set mine with 3/8 inch clearance.
I agree that an 11x6 is too large for a 40LA.
Fred

Harry Lagman

Kostas, I agree with some of the others: the 11 x 6 APC prop is a bit too much for the poor old .40 LA. An MA 11 x 6 would be a better bet (1bout another 1000 rpm), or maybe an MA 11 x 5 or an APC 11 x 4. Depending on the airframe, an APC 10 x 6 might work too.

It's unlikely to be doing more than about 9 and a half to 10 grand with the APC 11 x 6, which will badly hurt fuel draw.

Kostas1

Guys here are some pics to see exactly how my setup is.

It's kinda weird the engine to run excellent on idle,WOT and midrange+transition and not run good once vertical....d@mn it's frustrating.[:@]

http://img687.imageshack.us/i/hinges001.jpg/

http://img340.imageshack.us/i/hinges003.jpg/

http://img503.imageshack.us/i/hinges004.jpg/

And my other loves airplanes...

http://img260.imageshack.us/i/hinges006.jpg/

http://img510.imageshack.us/i/hinges007.jpg/

rcdude7

My Feedback: (264)

Kostas, give that poor engine a break! A 11x6 is too much prop. Your .40la has the power of a .25BB engine, maybe. I have found that a 10X5 is a very good prop for the .40la. As for your problem with the fuel draw, do you have the tank placed close to the engine? If not, maybe the engine can't pull the fuel that far when the plane is held vertical.

MartyH

My Feedback: (16)

As nearly everyone else has said, the 11X6 is too much prop for a normal 40 and the LA is a little weaker than that so it's definately too much prop so start with changing that to a 10 X 5-no more than 10 X 6 for sure! As for this being a "wierd" problem, there's nothing wierd about it really as this is exactly why you hold a plane vertical. You are looking to see if you have this problem. It is likely that you need to richen the high speed needle a few clicks even if it means giving up a couple hundred rpm when level so that when vertical it won't lean out so much and quit. THAT condition will ruin an engine in short order if you routinely fly it that lean.

Hobbsy

My Feedback: (102)

Kostas, when you use too large of a prop the airflow velocity through the carb is too slow reducing fuel draw. Also, where is the airbleed screw set, it should be about halfway across the inlet hole or slighly more closed.

freakingfast

My Feedback: (3)

I think your fuel line slipped off inside the tank. To test for this, just put a little fuel in and try to run it. No go? Than that's it.

MJD

My Feedback: (1)

It's not all that weird, until you systematically try the good suggestions given and start eliminating variables. Then, if you still have a problem it is weird. And FF's tank suggestion would sure as heck do this. So would, depending how things are positioned inside the tank, reversing the fuel and vent lines.

MJD

ronwc

My Feedback: (404)

Change to a 10x6 APC prop, take out cone inside muffler, take off any exhaust extensions, shorten fuel lines as short as possible - these all bog down your engine and make it run hot and lean - then run slightly rich till broken in -

Kostas1

Hobbsy,
thank you for your suggestion,

but mY English didn't help me understand what exactly you meant....[]

Today ,
i checked that the correct line goes to the correct place,

and the tank's position cann't change because there isn't any space inside the fuse to move it,lower it or place it higher.

I believe that it's in the correct orrientation with the carb center line!

rcdude7

My Feedback: (264)

Hobbsy is telling you that your engine is not turning fast enough with the large prop, and this is causing poor fuel draw through the carburetor.

earlwb

Like they all stated the 11x6 is too big of a prop, try a 10x6 or evena 10x5.  If your Extra is designed for slow flight a 11x4 prop mightwork Ok for you.
In looking at your pics, it looks ok, except the remote needle valveshould be lower and inline with the carb. When you look at the factorysetup, you will see the remote needle valve inline with the carb andmounted to the top two screws of the rear crankcase cover.

now it is possible the fuel line inside the fuel tank has a problem.But if the engine is running Ok until you point the nose up, then youhave a fuel draw problem. The first thing then is to go to a smallerprop and get the RPMs up so the fuel draw is improved. Then check themuffler vent fitting for the fuel tank, it may be partially obstructedor blocked off.

Kostas1

Ok guys,
i will try your suggestions tomorrow!

As you see,
yes,
the needle valve ,that way i installed it is higher than the carb!

still4given

The needle valve location is not going to matter. All it is is a valve. The relation of the spray bar in the carb and the center-line of the tank is what is important. Almost every person here has suggested that you switch to a smaller prop, yet if haven't seen in any of your posts that you have. This may be the single most important thing and easiest to try, Have you done it yet?

You said the engine is used. It may just not have enough compression to create good enough fuel draw to pull the fuel straight up. Especially if you tank is not right behind the engine. Did you check to see if the clunk line has come undone inside the tank? Very common.

Vacaman

You may have a loop on the clunk line, inside the tank, and its against the front side.
Also, some time ago a friend of mine had the same problem on a engine that he bought used. The engine had a screw inside the muffler, after the baffle. When the engine pointed up, the screw jump to the exit hole and shut the engine off.

grinder-RCU

My Feedback: (1)

Check fuel line inside tank for cracks. Fuel line coud be cut inside the tank where it comes off the brass tube. Also clunk could be stuck forward in the tank resulting in a fuel draw loss when held verticle.

Grinder.