Hello,

I have a Trainer that I am getting ready to get out to the Field. Today I was running in the Engine, a Magnum .90 4 Cycle. I am using the Standard Great Planes Fuel Tubing to connect the Tank to the Engine. Here is my problem, the Tubing gets so slippery from the Oil in the Fuel, it will just slip right off the Carb and the Fuel Filter. The Whole Assembly literally falls apart. I am Using the Cool Power Omega Fuel 15%. Should I try a different brand of Tubing? Or a Smaller Diameter?

Thanks,

Joel

Try a smaller diameter. I've never seen fuel line that will slip off unless it was too big

wow, I'm glad somebody had this problem before me

As most probably know I am in the process of beginning glow planes and now I know what to do if this ever happens to me

Good Luck

the standard size should be the right one, but with fuel line that doesn't want to stay put or on planes where a fuel line that might fail could be fatal,small size Zip ties work well to secure the fuel tubing so it doesn't slip off the barbs for safety.
this is a OS120 pumped all the lines have zip ties for security,but make sure the lines are tight fitting even before you use the ties there just a insurance policy not a substitute for the right fit.

Use "medium" tubing and get rid of the filter. Filter your fuel in the supply can and in the tank. Inline filters are prone to leakage.

Dr.1

Is this (no inline fuel filter) common practice and recommended for beginners?

I found my problem. I compared the Great Planes Line to the Fuel Line that came with my Filling Station. The GP Line is alot more softer then the Dubro Line is. So I am going to get another brand of Fuel Line. I don't think I like the quality of the Great Planes Fuel Line.

Dr1, I've used two different make filters and have never had a problem with them. In fact, on my four strokes, I use two. One between the muffler and the tank and the other between the carb and tank. I've never had one leak.

There really isn't anything wrong with the soft tubing. I would check the line size. It should fit very snugly on a piece of 1/8" brass tubing. If it is loose, it is to big.

This may be a comment from way out in left field, but is you tubing snug between the tank and engine, IE is there a bit of extra length. If you have things to tight on length, it will pull off. You want you tubing at least 1/2" longer than needed. You don't want any kinks in it either, so take that into consideration when cutting to length. I put the tubing on the tank and leave a foot or more out the front of the plane. Then after eveything is mounted, I route the tubing to the nipple on the engine making sure there is not kinks in the bends and then cut it 1/2" longer. Once I have it to length, then I figure where I want the filter and cut the tubing there, one cut which gives me a bit extra length again.

Two reasons for the extra length. First it prevents the kinks that shut off fuel flow. Second most tubing failures are right at the nipple or tank tubing. If you have a bit extra line in the hookup, you can usually fix a leak at the field and do a full up repair later.

In addition to the zip ties, you can cut a short, 1/8" long, piece of tubing and put it over the end of your main tubing. Put your main on and the slide the short piece up and onto the nipple. Nothing slips by this.

Don

Added" A little extra length is good, al lot is bad. You don't want the tubing flaying around in the air stream.

Common? Probably is, but maybe half the experienced modelers like inline filters and half don't. Depends if the modeler uses tubing that fits to begin with. The right size won't come off and doesn't need help staying on. And a lot of modelers know how to keep filters screwed tight and put fuel tubing on. Plus, having a filter near the carb often improves engine runs. Truth is, learning what fits what is one of the things beginners have to accomplish.

Are inline filters recommended for beginners? The ones who are apt to not maintenance their stuff over time and can't get the hang of putting tubing on that stays should probably keep things as simple as possible. The use of fuel filters is a sensible thing to do. It just depends on your own attitude and capability where you use them.

They can actually serve a very useful purpose. See the filter on the deliver line to the carb? That model has a simple two-line tank. I use the delivery line as the fill line. The line to the filter from the tank is disconnected to fill the tank. It never comes loose and doesn't come close to needing zip ties or whatever. The tubing fits the filter nipple and the nipple is perfectly adequate in length. Component selection is one skill beginners will acquire over time. That filter has been in use since the 80s. It's never had a hose come loose. And it's been cleaned out too many times to count. Didn't have anything in it most times. And I had no idea how anything gets into it the times I've found stuff. Still, it's worth having there. I started using inline filters back in the 60s. They've never been a problem of any kind. Been useful where they can be used as a "gas cap" and have trapped stuff as well. I also use a filter in my fuel delivery system. But stuff still shows up in the inline at the carb. Who knows how it gets there. Who cares, if they have a filter that stops it.

"FatOrangeKat", it isn't "common" but a lot of people recommend and use them. To those people: congratulations. I believe if your fuel is clean when it comes out of the supply jug it will be clean when it gets to the engine. A filter can clog, causing endless tuning problems, and the two filter connections are just two more places for leaks to occur.

I use a sintered bronze filter in my supply jug and an inline filter in the supply line. I usually use a sintered bronze filter in the tank. I have never had a problem with dirty fuel, nor do I have many engine tuning problems.

Dr.1

Ever drop your supply jug hose on the ground? I picked mine up awhile back. How it got there, I got no clue. And how the stuff that gets into my inline fuel filter got there, I don't actually care. By having a filter to stop it, I don't have to rely on belief. Good thing about our hobby is there are perfectly good components that when used correctly can solve whatever problems an individual encounters. And they can be used or not, depending on what is encountered.


A filter can also be checked and cleaned out. The possibility of a problem is just a possibility. The probability of it happening is worth consideration. Since fuel hose that fits an adequate fitting has almost zero probability of leaking or coming off, the maintenance schedule that works for checking a filter will work for inspecting hose connections. Simple maintenance might not work for some people. It does for others. If the shoe fits..............

"congratulations"

BTW, the filter in the tank should suffer from exactly the same problems one 3inches down that same delivery line would suffer. It can come loose and it can "clog causing endless tuning problems". Matter of fact, that one in the tank IS an inline filter. It's just in a different place in the line. And you've not had problems with the inline filter in the tank, why risk it clogging or coming loose. Same probability exists. However, a filter closed away in a tank can't be inspected or cleaned if necessary and the connection maintained as easily as a filter out in the open.

Since the in-tank filter has proven in-line filters to work well without giving endless tuning problems it stands to reason the one more readily available would give identical service.

But the good thing about our hobby is that very often there are a number of "best solutions" that work equally well.

But the good thing about our hobby is that very often there are a number of "best solutions" that work equally well.
Yup. I know what works for me, you know what works for you, and the OP will take all the advice from everyone and decide what works for him.

If you've used filters and not had problems with them, good for you. And since I've not used filters and not had problems with dirty fuel, good for me. IF my fueling probe gets dropped, it gets well flushed and wiped off. I perform maintenance on my planes where it's necessary, da Rock. Since I don't use filters, I don't have to worry about them, now do I?

And they can be used or not, depending on what is encountered.
And since I haven't had any problems, I choose to not use an unnecessary piece of equipment.

Dr.1

When I started in this hobby a nice person gave me a filter. I still have that filter from years ago and have never taken it apart to have it cleaned. It has been backflushed as regualr maintance to be cleaned.

When I see a beginner, and if they do not have a fuel filter, I will give them one of mine. Fuel can be filtered when the tank is filled but contaminates will get in. The exhaust system pressure also puts contaminates into the fuel tank, combustion by products ect, and if unfiltered return full circle to the needle valve, usually to cause problems.

[link=http://www.pspec.com/fuelfilter.asp]http://www.pspec.com/fuelfilter.asp[/link] has a very small filter that goes inline to make sure that your engine gets clean fuel. These are marketed towards pylon racers to protect their very expensive engines. Also very good advice here about filters.

Richard

Although Dubro (I think it's Dubro) makes a less expensive one than this

http://www3.towerhobbies.com/cgi-bin...&I=LXXF25&P=ML

I use this sort of thing for two reasons: to reduce or prevent foaming in the fuel tank and to act as a filter, if I realy need one. It's there and works fine.

I found the Dubro one.. here it is:

http://www3.towerhobbies.com/cgi-bin...?&I=LXD741&P=7

CGr.

I have a fuel filter in my fuel line from my fuel jug. Thats plenty for me.
As for the fuel tubing size, well after yesterday I guess it just may be a crap shoot after all.
When you buy standard size fuel tubing you should expect just that. The tubing I put on my Kadet Senior kept popping off, luckily I had some zip ties with me. It was Great Planes I bought from Tower. I have new tubing on my shopping list for the LHS.

CGr, I have shyed away from this type clunk, thinking that as the fuel got low, it would start mixing air with the fuel as part of the filter would be above fuel level. Do you run into any issues with low fuel with this. I always though it would be better to have the single small inlet that would either pick up fuel or air, kind of a binary delivery. Maybe I'm borrowing trouble and missing out on a good idea???

Don

I've got some "standard" tubing I got from the LHS a bit back that has a hole so small that I can't get it off the barbs to fuel the plane. One part that I cut into had the hole off center also. Another length of a different tubing from the LHS that I was using for the pickup on my pump took a dislike to Cool power when I tried it. I had been using the tubing for over a year with Omega and at the half gallon mark with the Cool Power, the tubing broke off at fuel level and droppen in the jug. When I fished it out, it was gooey and crumbly below fuel level and like new above. I ditched the remainer of the jug and went back to Omega.

So, Tower and the LHS both seem to be a crap shoot for getting good tubing. Where to go next???

Don

I've used the sintered ( sp? ) bronze ones to help LOWER fuel foaming problems which they are advertized to do.

They work very well at this.

I compared using one of these on a tank which was being subjected to vibration at a specific RPM. With a standard small hole clunk I'd get foaming... with the sintered brass clunk, no foaming.

The brass clunk is supposed to break up any bubbles.

Yeah, the reason I started using them is for that very reason. I think it was all started with my Excellerion 90 and that crap Evo 100 NX engine. It was a suggestion to try to fix the problems I was having with this setup. So, I went ahead and replaced the clunk. It did not fix the problem but I left it in.

Eventually, though, the engine was replaced with an OS 1.20 AX and the problems went away, but I kept the clunk in there and it has not caused any problems at all. But, I always try to remember to time my flights so I don't run low enough on fuel to see any problems as you mentioned.

Since then, I pretty much just install them in my planes. It's one of those things, I guess, that we gain confidence in for one reason or another, and even though there is no logical reasoning behind this, we continue to do so.

CGr.

Where next? Beauty of our hobby is that it supplies us with a flood of excuses. Now you HAVE TO go to that LHS in the next town you've heard is so good. It's not your fault that you HAVE TO find better tubing!

hehehehe

One of the tricks the experienced guys picked up long ago (after the trick of accumulationg excuses for everything) is to keep an eye out for items on their list and stock up whenever they find one. Keep an eye out for tubing. Last time I was in the best LHS around here, I was with a newbie. He asked why I was buying 2' of fuel tubing. When I said, "because it's good tubing" he laughed himself silly. Guess who will laugh last. I almost made him walk home, btw.

BTW, guys if you do start to use a fuel filter, make sure you remember to check the sucker after a few weeks, and then on a schedule based on what you found that 1st check. Mine almost never have anything in them, but I've found problems in the fuel line routing on a number of new airplanes the first time I checked their filters.

Maintenance pays big dividends.

After many, many years of building tanks and competing in an event where the flight time was VERY important and there was no throttle, and trying lots and lots of designs..................................

The type CGRetired suggests is excellent. It's got a huge filtering area and does seem to insure no bubbles from foaming fuel for one. What you've suggested, having just a single small inlet is a good idea too. But what you are worried about actually doesn't seem to happen.

What happens with any inlet is that the very instant it is uncovered it will suck air. Size doesn't matter. As soon as the fuel level uncovers the inlet, you're out of gas. The tank won't ever be, but the engine will be. A small inlet will be able to pull a higher percentage of the fuel out before it sees air. A larger inlet will leave more fuel in the tank. In theory, the big inlet should be more apt to cause a stumble just at empty. In practice, it usually doesn't. And when it does, it's just a stumble, not a lean run. And that is actually a good deal, not a bad one.

The filter CGR advises is a good idea for sure.

da Rock,
pretty Tiger 60...Luv those planes!
Mike

I think I remember that thread too... that's the reason I started using them as well. Never got the Evolution 1.00NX to work right, but I'm about to try again... this engine really bugs me...

I didn't quite believe in those clunks until I had a foaming issue in another plane which the Dubro clunk eliminated. They also prevent problems if your lines are just long enough to contact the back of the tank on acceleration.

I had a plane that I had setup with what I though was enough of a gap, and it turned out that as it accelerated the tubing would stretch just enough to let the clunk contact the back of the tank, causing an overly lean condition and deadstick.

The Dubro clunks prevent this from even being a possibility.