My tank is approximately in-line with my carb and the feul outlet is about 4" from the carb. However, I have about 12" or so of feul tubing from the tank to the easy feul valve and then back to the carb. Other than maybe a few extra flips to prime, will this create a problem running my engine? I also have about 10-12" of feul tubing from the tank to the muffler exhaust nipple, will that matter? Thanks.

Joe,

I don't think there should be a problem with flow restriction, because the flow rate of the fuel is so low. The muffler line should not be a problem either, as that flow rate is also low.

banktoturn

The only way to really tell is to try it.

The beauty of fluid mechanics is that if the source and destination are only 4" away, you could theoretically have 100 miles of tubing between them and it would work exactly the same as if there were only 4" of tubing. Of course it's not quite that simple, but in theory...

How come so much fuel tubing?

Thanks for the quick replies. I just got home from work and will give it a try before the nights over. The reason for the 'excessive' length is that with the cowl on it's very hard to get access to the nipples on the eazy-feuler valve so I need to have enough length to leave the cowl partially off, attach it, then slide the cowl on. I could remove some length from the exhaust tubing but getting the tubing 'threaded' through the firewall while I was putting the tank in required this length and I hate to trim it knowing if I ever have to pull the tank I'll have to have another longer piece to do so. I'll let you know how it works later tonight.

- Joe

ARGH! Just spent two hours )@#I&%-ing with this thing and no luck. THEN I find out my glow driver is DEAD so I hook up my power panel (I don't have a driver for it) and run two wires from it to my remote glow adapter (from the glow driver plugs). NOTHING. Nothing. Maybe there's something wrong with my tank?

12 inches is a whole lot of fuel line when you are not using a pump of some kind, it doesn't matter that the tank is only 4 inches away, the engine now thinks it's 12 inches away just as if you had moved it to the cg.

If you are having fuel supply problems, you should still be able to get it to turn over.

If it's flooding, close the needle valve, and spin it for a while. The excess fuel should clear out, and it will start up.
If it's too lean, prime it more, it should start.
If it runs for a few seconds then quits, maybe you have a tank problem.

If you can't get it to run at all, it's probably not fuel.
When I get stumped, I look for carb air leaks, try a new glow plug, then try a friend's glow driver.

Good luck.

Ken

There are ways to thread the fuel line through the firewall without having to have excessive lengths of tubing. I usually use a piece of wire pushrod stuck in through the front of the plane to guide the line out.

I would also ditch the "Easy Fueler" and go with a 3-line tank setup. The third line is a dedicated fueling/defueling line that's normally plugged off with a "fuel dot" or some other plug.

Trying to set up a new engine with the cowl on is an exercise in futility. Take the cowl off and get the engine issues taken care of, THEN put the cowl on.

hobbsy, no offense, but you're partially incorrect. It's a matter of fluid mechanics.

Take a piece of fuel tubing 4" long and a piece 36" long. Stand the 4" long piece straight up on end, and coil the 36" piece up so it makes a 4" high pile. Fill both pieces with fuel and measure the pressure at the bottom. Even though there's 9 times as much fuel in the 36" piece of tubing, the pressure is the same as it is on the 4" piece.

The concern with putting the fuel tank on the CG has to do with climing/diving maneuvers. If all the plane did was fly level, you could put the fuel tank in the tail, and you wouldn't see much difference, assuming no air bubbles ever made their way into the fuel line. As long as the fuel tubing remains completely full of fuel, the siphoning action would negate any additional horizontal distance between the tank and the engine. However, planes don't fly horizontally all the time. In a climb, the siphoning action works against us. In a dive, the siphoning action is working for us, but it's working for us too hard! We put our fuel tanks in the front to minimize this change in "head," which, IIRC, is the vertical distance between the bottom and top of the fluid in the system.

MK, it's the same static but not when you want to move it.

12 inches is too much fuel line. If you "MUST" have that much line I would recommend that you get a cline/perry fuel pump or for a unreliable alternative, put a check valve between the muffle and the tank pressure line. This should keep a higher than atmospheric pressure on the tank to help force the fuel through the line.

If the engine is drawing about 1 oz. of fuel per minute and you go from 4" of fuel tubing to 12" of tubing, It would have about the same affect as lowering the level of the tank about an inch with 4 inches of fuel line. Some engines really don't like a tank that low. That doesn't take into account any other losses other than the length. It might run more like it is 1.5 inches lower once you consider the other losses. I always run a third line and use the least amount of fuel line possible. Yes, static the pressure on both sides is the same as long as the engine isn't running and drawing fuel. Once the fuel starts moving it isn't static any more and there is a pressure loss in the line. The faster the fuel moves, the higher the loss.

We never went over fluid dynamics in physics but from my understanding of surface tension from chemistry I can image a small diameter feul line would have considerably more friction than a larger sized pipe, on a oz per oz basis. In any event, back to small tubing with 3rd feul line for filling. However, do I need to add a clunk to the third line so that I can de-feul it as well? If so do I need to worry about both clunks getting tangled?

On a side note: Today I primed the engine and ON THE FIRST FLIP it started. I'm afraid to try it again since it may not start the first time and I'll be bummed again

You do not have to worry about a two clunk, three lins system. I would recommend that you put a short piece of brass tubing in the third line to keep it at the back where you want it.

Line that cary liquid should be as short as possible lines that carry air do not.

Keep that brass tube for the third line bent up toward the top of the tank near the front, right next to the muffler tube. That way when you fill the tank and it spurts out the muffler tube, you can be sure it's full to the "brim". If the line is in the back, there may be a 1/2 oz less fuel in the system when it spurts out the muffler tube. Stub that third line off with a tight fitting socket head screw or anything else too big to fit in it very easily.

Let it dangle and go flying...stop worrying whether or not it will start again...it will.

jw

If you do this you cannot empty the tank through threw fill line.

Sure you can, but I usually empty the tank through the carb line.
The clunk screen catches any stuff and for my planes it's easier to reach than the carb line, than flipping the plane over on it's back and using the fill line.

It's a personal choice, but I think I've gotten better consistency in filling the tanks with the tube in the bubble top of the tank, above the fuel "surface" at full.

I have never tried running too lines in the bubble. I guess I will try it with my conversion and see how it works!

You can leave one out of the bubble, close enough is good enough.

The key is to get it high in the tank so you can get it full.
a fraction here or there is ok.
Also, if it's in the bubble right near the other, you might get a false "full" spurt out of the muffler line.

so get it close but angled away from the muffler line.

we're splitting hairs now...but the ultimate answer is to shorten your fuel lines and get a third going.

have fun,
jw

I had a small experience that I think would make a valuable post.

I was out flying yesterday. A guy that was just starting to fly after a 5 year hiatus was out with a new trainer. He also bought a used Sukhoi from the LHS with a ST 90 on it. I think it was an old Byron's kit. He asked me to put a trim flight in on the Sukhoi. I checked it over quickly with the wing on. After checking the controls I noticed there was a Dubro quickfiller back under the canopy. So I expected the worst.

Well, I decided to give it a try. We fueled it up and I set the needle at 3 turns out to start with. The motor would finally run at about 6 turns out. I backed the needle off a half turn and it passed the nose up test.

About 2 minutes into the flight the engine leaned and died. It was a miracle that I made it back to the runway. It had a high sink rate. I made the runway by about 2 feet.

After it was on the ground we took it apart. It just so happes that the fuel line runs from the clunk back to the fueler and then up to the carb with no pump. The plane was built such that there was no access to the interior plumbing. By hacking a small hole in the engine box we were able to re-route the tubing and out the quickfueler in the cowl. We cut nearly 2 feet of line between the tank and the carb. It is now about 6 inches total length. I pulled the Pitt's muffler and took a look at the piston. It was very black and had been run very lean for a long time. Probably during the latter half of each flight before the deadstick landing. The engine is all but ruined.

I'll bet the original owner was unable to get the engine to run well with his setup and sold the plane. It got dark and we weren't able to fly the plane after that so I don't have results of the fix. I'll post them if I ever see him again.

While the engine may be warn, it should not be warped. How is the compression? I take it that while the engine is running it is strong.

The compression was not all that great and it was not all that powerful, but it ran. Also the piston was badly scored. Possibly from the element of a couple of blown plugs. I'm sure that the liner was pretty ripped up as well. I'm sure he will need a new piston and liner.

Joe, It sounds to me like (correct me if i'm wrong) you made the mistake of mounting the quick fueler on the canopy itself. Try mounting it on the firewall and accessing it through a hole in the canopy, see the attached picture. The fuel line need only be an inch or two longer than if it went straight to the Carb.

Bob C.

Here's another with the cowl installed.

"canopy" excuse me, I mean cowl. I've been working all day fitting up the canopy on my H9 Edge and I've got canopy on the brain.