Engine allways quit

[malehooker_24]

Hi again I have 4 helis and 5 airplanes and i fly them all but the problem i allways have outa all of them is i can fly about 3 minuites at the most then the engines quit everytime and i have to glide in . the helis ive never crashed but im scared to get em over 8 feet off the ground .Ive adjusted the needle valves everyway and other guys have adjusted the at the field and still they.ll quitIf i ever figure this out ill have to learn to land with an engine running because ive never landed an airplane that was running. What am i doing wrong?? Thanks John

[boomerace]

Originally posted by malehooker_24
Hi again I have 4 helis and 5 airplanes and i fly them all but the problem i allways have outa all of them is i can fly about 3 minuites at the most then the engines quit everytime and i have to glide in . the helis ive never crashed but im scared to get em over 8 feet off the ground .Ive adjusted the needle valves everyway and other guys have adjusted the at the field and still they.ll quitIf i ever figure this out ill have to learn to land with an engine running because ive never landed an airplane that was running. What am i doing wrong?? Thanks John
Sounds like a Gasser that doesn't have the fuel tank vented properly. Runs until tank vacumn overcomes the engines ability to get fuel! My best guess!
boomer

[t_predator90]

this brings back some horrific memmorys of my first 2 months.... you fly for about 2-4 minuets and then the @^$#! engine quits... I had air bubbles getting into my engine constently... take out the tank, check ALL the tubes and check the rubber block to make sure its in place, and most importently (this is what was the matter with mine), check that the tube INSIDE the tank is connected!!! If not, then when the fuel reaches below the line where the little black piece is, just air come into the engine, instead of the tube inside with the waight always being at the bottum of the fuel tank...
Hope that helps! I know how frustraiting it is....... :mad:

[Up&Away]

You probably don't want to hear this, but I'll say it anyway...
GO ELECTRIC!!!

But seriously, like Boomeranc and t_predator, it sounds like either a fueltank vacuum, or the opposite, your engine sucks in air instead of fuel.

Take out the fuel tank and open up the fuel top. Typically this would be a screw that pulls a stop into the tank opening. Make sure all fuel pipes are intact. If possible, don't take any chances and replace them. Inside the fuel tank, make sure the fuel pipe with the weighted filter is attached properly. They tend to come loose after a while. At the same time also make sure that the air inlet is in place properly and is bend up. Once all that is checked, re-assemble the tank, and make sure there is no leak (either air or fuel). Atach a clean fuel pipe to the tank and with your mouth blow into it, while holding a finger on the other opening. You should not be able to blow air in. If you do, you have a leak. Better change tank.

Hope this helps! Good luck:D

[Star-Rider]

Its either the above mentioned advise, it could also be that you have connected the vacuum line to the carb? Try switching that.

[Tony Oliver]

Are you using the pressure tube to the silencer? If so, check that the nipple on the silencer isn't blocked with gunge!

The pressure isn't great and is a frequent problem, particularly on engines which are not cleaned out after flying - the nipple gets caked with gummed castor and nothing passes through, hence the comments about vacuum forming in the tank.

An alternative answer is to take time out to run the engine in the model on the ground (tied down so it can't move) and carefully watch the fuel line as it enters the carb.Run the engine slightly rich (almost on the verge of 'fourstroking'). If you see any bubbles at all you need to check everything back to the tank. Don't assume there are no pinholes in new tubing - I bought a few yards of tubing once which turned out to be faulty throughout its length. Not only does it start to pull air in. It is easily cut at the point it's attached to the clunkand the tubes in the tank. Also make sure the tank level is right - try to arrange the carb fuel inlet so that it is 2/3 to 3/4 up the tank.

The final consideration is the carb leaking air and reducing suction. An engine will always take in air rather than fuel if it can.

Leaking 'o' rings, poor fitting barrel, airbleed to far open are also possible causes.

The important thing is to eliminate one cause at a time. Don't change two things at once.

Tony

[bobbdd]

If this problem is happening with all your planes and helis,it must be some basic thing you might be doing wrong.One small factor.It is starting to sound like a fuel problem,but you should also check,your idle set up, glow engines will go down to a nice idle,but not always hold it for long,and bog a little on the throtle up.Idle settings can be tricky. If you have an old-timer around they are always a great help!!

[hackken]

John, you state that you have 9 planes and they all have this problem?? If none of the suggestions made thus far have helped, consider that you may be adjusting your engines a little too lean. As fuel is consumed from the tank the fuel level in the tank drops and causes the motor to run a little leaner as the flight progresses and the engine dies from being too lean. I have seen this situation many times in years past and the remedy is to have the fuel tank situated at the proper height in relation to the needle valve and be certain that the flight is started with the engine slightly on the rich side.
I find that for me the best needle valve setting is done by richening up the setting until the engine 4 strokes and then VERY, VERY gradually leaning it down until it just starts running smoothly (2 stroking) and leave it at that setting. Never adjust it on the ground for maximum RPM as this will usually result in the engine quitting lean partly through the flight.
Also be certain to use a good fuel filter in the line from the tank as it only takes a small piece of debris to get lodged in the needle valve and cause the mixture to go suddenly lean. If you fill your tank by unplugging the line at your carburetor then any fuel going to your tank will be going in a reverse direction through your filter and any dirt in the fuel while fueling will accumulate on the engine side of the fuel filter screen and will be drawn into the engine when the engine is started. Always fuel up from the tank side of the fuel filter.
One other thought comes to mind, and I experienced this for several years and that is if your fuel has all castor oil (no synthetic) and if you stop your motor by squeezing the fuel line, the fuel line and filter will remain full of fuel and if it is stored like this for sometime, the castor oil will congeal into lumps of goo in the fuel line and filter, which will have a tendency to clog the needle valve. Sometimes this only shows up half way through the flight the next time you are out to the flying field. I find the best answer to this is to simply blow out all my fuel lines and filter as soon as I get home from a flying session. I mix my own fuel and use 20 percent castor oil (I consider it the best lubricant for engines) but it does have these problems associated with its use. If you are using commercially available fuel with little or no castor in it, then I doubt if this would be a problem.
There is one other possibility that I don't think was mentioned and that is fuel foaming due to vibration, however, I do not think it would be your problem in all 9 planes. Make certain that your tanks are wrapped in foam rubber to minimize vibration in the tank. When I mix my own fuel I add 4 drops of Armor All per gallon of fuel and find that this is quite effective in stopping fuel foaming. I believe most commercially available fuels have an additive to reduce fuel foaming.
Sorry to be so long winded, but hope that you John, or others may find something of value in all this. These are my observations from many years of flying glow motors.

[bcuda]

Try someone elses fuel.

I know it sounds funny but back when I bought my first electric fuel pump, I mounted it to the gallon fuel can. I hot glued the fittings in the top of the can and had a very similar problem. I could get about 20 -30 feet off the ground and the motor would quit. It took a while to figure it out but when I used someone elses fuel, my motor ran great. The glue must have contaminated the fuel.

Bob