I had a problem simular to this with my trainer. Engine ran good no problems with it at all. Had plenty of power for a 40LA. Fuel lines had no holes and even replaced them but for some reason the engine would quit while flying. You could deadstick it in and restart the engine and put it back up and fly around for a few minutes and the same thing would happen. What I figured out was the problem was the trottle wasn't set to the right length and then when I throttled back to far it would kill the engine. When I did my ground check everything looked ok. But like I said it was only when throttling back to a low idle did the engine die. Reset the linkage to the right setting and everything is great now. Also you might think if you've been flying in the cold the expansion and contraction of materials at different temps will cause the control rods to change lengths and cause problems

HTH
Brandon

I need a place to store this picture. I'll keep it here in Ken's thread so I can find it if I ever need to use it. [8D]

Yep. I did, but he has swapped out the tanks and plumbing two, or more times.

I agree, this is a classic example of a pin hole in feed line.

Ken,
Sell your plane to someone else with the agreement that when he or she gets it running, you can buy it back for the same price.

The reason being is it sounds like you need to totally remove yourself from the problem. I'm sure there is nothing fundamentally wrong with your systems. These planes are reliable and do run well, someone else needs to get in and fix it.

Obviously it's not an engine problem, it's a setup problem. Let a fresh mind look at it at their leisure and the problem will be fixed.

DYNODAN -- GREAT ADVICE

NEXT TO THE SUGGESTION REQUIRING DYNAMITE, THIS IS THE BEST I'VE SEEN. OBVIOUSLY, I'M TOO CLOSE TO THE SITUATION.

KEN

MAN KENB85,PEOPLE SURE ARE GIVING YOU A HARD TIME ABOUT YOUR CAPITAL LETTERS,BUT I HAVE TO ADMIT CAFFINEMANS POST #52 IS PRETTY FUNNY!HOPE YOU GET YOUR PLANE FIXED AS I HAVE NO ADVICE FOR YOU.I THINK EVERYBODY HAS COVERED EVERYTHING I COULD POSSIBLY THINK OF.GOOD LUCK.

OK people -- I don't really know yet what the problem is but I found out how to stop it. (By the way, I hate these lower case letters but in order not to offend some people's delicate sensibilities I'll try to live with them.)
--ON BOARD GLOW PLUG STARTER -- I installed one and now the plane lands with the engine running. Sometime I can hear it cutting out but before the engine stops it catches up again. And I've decided that when it was cutting out it was in level flight at less than full throttle. The starter is adjustable (it reads the throttle position) and it's adjusted so it's on all the time except when the throttle is above 3/4 open.

Ken

Ken - I don't go along with the "all caps = yelling" thing, but it makes it hard to read. About the same as when people write 200 sentences with not paragraphs.

Anyway, I didn't read back. What position is your engine mounted in? Upright, inverted or sideways? Other?

It sounds like either you have the wrong kind of plug or your idle is too rich. When you need a glow igniter to keep your plug lit, it means it's not staying hot on its own.

- Paul

I second the cowl issue (if you have one). This happened to me on my Sukhoi, ran good on the ground but once I got into some hard flying it would bog down and die after a few minutes from over heating. I have a TT Pro46 on it, my friend has the same plane with the same engine and it did the same exact thing. It took awhile but I finally got it right. I cut the cowl out a little more, and it took some needle valve tweaking. Good Luck, I know its frustrating.

Actually there is one other solution...the good ole Polish figure 9. Did exactly that with a Sig Kobra years ago. Had the same problem as KENB85...tried everything. Last ditch effort was to cut the top of the fuse and raise the tank out of the fuse. Still not fixed so in she went. What can I say....16 years old - high temper - no patience, lol.

Hi Ken,

You say your tank is 3" behind the firewall? Any reason it's so far behind? Maybe the extra fuel line behind the firewall flops around when the plane is in motion, leaning out the fuel supply to the carb?

Your tank is extensively padded to prevent foaming, but is it rigid enough? What kind of padding are you using?

What about the opening in the firewall for your fuel intake and pressure? Is it possible it's too small and restrictive?

About the All caps thing, I do have a suggestion which might help you in all your computer applications.

Assuming you're running windows, look in your control panel for an icon called Accessibility Options.

(Start-> Settings -> Control Panel -> Accessibility Options)

Choose the Display Tab and check "Use High Contrast"
Click Settings

Here's where you can play with it. Click the Custom Option and choose a setting from the list.
I haven't tried them all, but you'll probably be able to find something easy to read.

The beauty of this method is that you'll be able to read anything on your computer clearly, yet when you contribute in a forum, you can use lowercase letters and not offend anyone.

Oops, sorry, lots of info in this thread, it was hard to find it.

See you said you mounted tank in Polyfoam.
I'm not familiar with that.
Is it like the rubberized heavy foam padding sold for RC to cushion rx's?
Or is it more like a synthetic lightweight kitchen sponge?

If the latter, it might not be dense enough to prevent the tank from moving inside the tank compartment.

Where did you locate the screw for the forward hach whenyou put it in? Is the screw punching a hole in each brand new fuel line you put in the airplane?[&:] (BTDT)

Thanks for all the suggestions but I'm afraid this thread has grown entirely too large and has gone on too long. If you read back (and I agree, it's too much to read through) you'll see that all these latest suggestions have been tried. And I've tried FAR too many things to list them all here.
However --patternwannabee-- what I had intended to say was that the tank is 3" behind the carb. which puts it immediatley behind and adjacent to the firewall. Also, poly(urethane of ethylene)foam is the industry name for what most people refer to as foam rubber (which is actually made of rubber). Polyfoam comes in lots of different densities. I'm using 3 different densities -soft , med. & firm -- similar to the "Isolastic Suspension" systems pioneered by the British in the '60's to stop vibrations at varying frequencies and some of the pads used are actually the "rubberized heavy foam padding sold for RC to cushion rx's" (real foam rubber). Densities are aprox. 1 pound per cubic foot to 4 pcf.
I think that for now, I'll just fly as much as I can and depend on the onboard glow starter to keep it running. On the last flight of the day last Sunday, it didn't cut out at all but it was late and I had to go. Maybe it has already fixed itself.

Ken

This looks like a older tread but if your still watching it you said you have no fuel in the line to the carb after it stops .so it runs out of fuel due to one of two things not enough tank pressure , or a hole in a line, pinched,etc, somewhere .What I didn't see was did you use all the same type of engines if so did you use the same muffler .A leak between the muff and the exhaust port will cause a pressure prob in the tank .I use a gasket to stop this prob .
One more thing My 46 SF Hated the stock muff if I ran it where one would think it should run on the ground it would die on me every time .I had to run it very rich and after it got in the air it would lean itself out and run fine .The fix for this engine was a diff muffler After that it was not a prob again.
One more thing you said the tank was 1/4 of a inch below the needle valve or did you mean the center of the carb?
One other thing that just hit me it this you can pack a tank so tight with foam theres no give and it will foam the fuel like crazy.

Ken,

I've read your entire thread, and, to be frank, I don't know how you've managed to keep your head with all this trouble shooting! Very frustrating.

The only thing I can think of to add is try installing a check valve on your vent side fuel line to regulate the pressure? Just a thought.....

Good Luck!

One thing that no one has addressed and could be very important. What color is your plane?

I would bet that you are using a prop way to big for the engine. Try a 10/6. all your problems will go away.

I had a problem like this on two engines that was caused by the stupidest little things.

Stupid thing #1. On one engine the line between the needle valve was such a length that it would vibrate like guitar string and choke off the fuel. After a few minutes the engine would lean out overheat and die.

It would run fine on the ground. Solution: install longer fuel tube between needle and carb.

Stupid thing #2. Fueline on another plane was touching engine head and as the engine heated up it would vaporize the fuel in the line causing engine to die.

Solution: re-route fuel line..

Drill out the hole in the clunk to make it bigger.

(I don't think I've read this yet)

I'm sorry but I got so fed up with this problem that I haven't looked at this thread since my last reply about 3 months ago. I really appreciate most of your suggestions (but not the ones about not using all caps). I've tried most of the suggestions several times (but not the ones involving a small amount of high explosive). The ONBOARD GLOW PLUG STARTER IS STILL WORKING GREAT and I haven't flown this plane without it in several months. You can hear the engine cut out from time to time but the glow starter saves it. I still don't know what the real problem is but I reached the point about 5 months ago that I didn't care any more, I just wanted it to go away. All of my other planes are still flying good and don't have this type of problem.

And if you're wondering about me using lower case now, I've recently started a home business so it seemed that since most people are rude and won't use all caps, I thought I'd just join the crowd.

And now for the advertisement --- If you need any tool design work done, send me a private message. I've had 40 years in the field including structural work, hydraulics, pneumatics, machining fixtures and test benches for aircraft hydraulics, pneumatics and fuel systems. This is why I'm so fed up with my engine stalling problem. I SHOULD be able to solve it but now -I still don't care what it is just as long as the glow starter keeps it running.

Hi again Ken,

I have some thoughts, mostly about the tank. Since you've been working on this thing, have you tried to start it and run it with just a quarter tank full? Like, pump 2 oz into an empty tank, and try to start it? I'm wondering if the fuel level has anything to do with it.

Or, when you assemble it, is there a chance a line could be getting squeezed shut, like the pressure line from the muffler, or the carb line.

And, as a straw to grasp at... could you strap a tank on the side of the plane, and fly with it there - strictly to see if the plane will operate in the air with a tank that has no lines pinched or running through the firewall.

That thing about the air deflecting off the carb in the air... I'm wondering why it wouldn't show up in the first couple minutes of operation. Still, it's a thought. You could strap a deflector on the front - or an inlet elbow that would point back toward the firewall, just to check it out.

Good luck,
Dave Olson

I had a .40SF that did the same thing in my Super Sportster and after tearing my hair out and I have two things that worked for me. Well, actually only one of them worked, but I did them both at the same time and I didn't want to figure out which one was the magic cure. First I put a piece of fuel tubing around the high speed needle to catch any air leaks that there might be. Second I put a one way check valve on the muffler pressure line so the pressure would remain in the tank and push fuel to the carb no matter what the throttle setting was. I did both of these and it cured my problem. I did the same things you did, changed the tank, moved the tank, tried different plugs, different settings, different everything and this was the only thing that worked. Fourmost makes check valves good for glow fuel. My first thought was you have a hole in the clunk line but since you have changed the tank, that shouldn't be the problem.

Good luck and I hope you find it!

Here is my two cents worth. The glow driver made it better. This tells me that this particular application requires a hotter glow plug. Or there is something causing the glow plug to cool off to the point that the engine quits. If it were a fuel delivery problem the glow driver would not correct the problem. Oh and about the caps thing, if you click on view in your browser window then click on text size you can choose a larger size for all text displayed. Ask me how I know this, I am also over 40

Mike, you're absolutely right. 99% of the questions women ask have no right answers. And I've noticed that for the 1% of the questions that do have a right answer I always choose the wrong one.

Now back to the engine stalling problem. I'm getting so many replies now that are duplicates or variations of earlier replies that it might be good to again list the things I've tried. There's no use in beating a dead horse but if it wasn't such a good looking plane, I might beat it . In the last few months I done several other things but mostly I've just flown with the onboard glow starter.

RECAP THE PROBLEM - Goldberg 40 Tiger II - runs good, flies good for a couple of minutes - then engine dies - mostly in level flight with power cut back some amount. I don't remember it dieing at full power. Engine is mounted vertical - tank adjacent to firewall with good clearance on lines.

THINGS THAT HAVE BEEN changed or adjusted or moved up to 5/30/04---
-engines - 3 ea. - 1 MDS 40 or 46 (I forgot which) - 2 OS 46 - these were all complete engines with mufflers & carbs that ran good on other planes - ran good on my engine stand - ran good in my plane on the ground - they would all run out an entire tank of fuel with no problem until I got in the air - I've run many tanks of fuel through these engines, they will suck the tank almost bone dry
-glow plugs - cold, med. & hot -- several known brands and some unknown brands - some 4 stroke plugs too - aprox 15 glow plugs - it now has an OS 8 in it
-propellers - aprox 8 from 9-8 to 11-6 - has a 10-6 on it now
-adjust carb lean - rich and everywhere inbetween
-fuel systems - 2 used tanks and 1 new one
-raised tank - lowered tank
-fuel components - clunks, hoses, etc. --aprox 6 times
-cleaned carbs and replaced o'rings several times
-rerouted hoses
-installed fuel tubing over needle for extra sealing & to hold it securely which it didn't need
-several fresh jugs of fuel
-check post 64 for tank mounting details - at first I just threw the tank in & went flying like Ive done on many other planes
-2 recievers & 2 transmitters that work good in other planes - I'm flying 4 different planes with one of the transmitters now

SOME SUGGESTIONS THAT HAVEN'T BEEN TRIED-
-Holy Water
-dynamite
-air cleaner
-check valve on pressure line from muffler (doesn't this continue pumping fuel through carb after you shut down?)
-drilling out clunk to larger size - Why? It's already double the I.D. of the tubing

I know I've left out some things (probably many things) but my mind is getting numb now so maybe I'll just fly it with the glow starter. After all, some situations may simply require an onboard glow starter, why else would they make them.