costarican_pilot

how can i elimate my bubbles on my fuel line? i cant get my 46 evlolution to run right! everytime i hit the full power the engines whants to quit because the bubbles increase... what can i do? at half power i dont see no bubbles and the plane flies good at the speed !

j.duncker

My Feedback: (2)

Sounds like your fuel is foaming due to vibration.

Have you hard mounted your tank OR have you a source of vibration eg unbalanced prop.

As a quick trial fit a smaller tank and lightly stuff foam around it.

jetmech05

Are the bubbles before or after the needle valve? If before the needle valve then jduncker is correct. If the bubbles are after the needle valve and not before it then the valve is leaking...Good luck

costarican_pilot

well the bubbles are in the needle valve that goes to the engine.. i really see a lot of vibration on the plane , my dad said i need to change the ball bearings because they r bad i really dont know if thats why my engine is runing bad? i crash this engine 2! but never hard!

Gray Beard

My Feedback: (-1)

It can also be a pin hole in the fuel line??? Either inside the tank or the outside line. If it's vibration you can try soft mounting the tank or go to a blader type.

Edwin

My Feedback: (2)

I'm just now fixing a problem I had on my engine that turned out to be inside the tank.
Edwin

costarican_pilot

if i check the full tank! what im really looking for it? holes? yes the screws are secure in the valve!

Edwin

My Feedback: (2)

My airleak was where the clunk fuel line connected with the brass tube in the stopper. I use gas instead of glow but the same applies. It needs to be tight cause when the fuel level drops down you start sucking a little air which screws with your mixture. I got five flights today with no problems. In the past, I've had pin holes in glow fuel lines because of sharp edges on the brass. Just little things you learn the hard way over the years.
Edwin

jaka

Hi!
Do the suck test!

Gray Beard

My Feedback: (-1)

And if there is a hole in the line inside the tank that would tell me what??
For outside lines and bung testing you plug all lines except one, submerge the tank under water and blow as hard as you can into the open line and look for bubbles while holding the open line closed. For inside lines you have to take the tank apart, you can plug them and do the blow test under water too. Unless the tank is brand new I replace the bung when putting it back together.

Luftwaffe Oberst

He's right. I have 3 Evolutions. One is a NT.46, another is a NX.46 and I have the NX.61. They don't give me issues very often. Make sure your low and high end is adjusted right. It's normal to get a slight hesitation if you idle your engine for a few minutes then slam the throttle forward suddenly... that is normal even if your engine is adjusted properly. That's the Evolution trade mark.

Another problem that gave me a issue the last time I flew my Hanger 9 Fokker is my glow plug vibrated loose. I guess I didn't tighten it down enough. This would cause the engine to run very lean and give you many "Deadstick."

The only time I get fuel foaming is if I have a unbalanced prop and my glow tank doesn't have enough padding. You don't want balsa or plywood touching your tank if you can help it. Get a smaller tank or sand down the wood around your glow tank so you can pad it and still have a nice fit. Before you do all that... balance your prop and try it. If it still foams then I would do the pading around the glow tank.

costarican_pilot

i found i hole in the line that goes to the valve to the engine i replace the line.. lest see how it flys this sunday.... any way if the problem perstis i will check the fuel tank.. and banlance the prop!!!! thank u all guys..!!!how can i know if my front berings r bad?

sebo

I read an article today that suggests to eliminate the foaming issue, two or 3 drops of silicone lubricating spray being added to a gallon of fuel will stop it from foaming. (Brian Winch....The Oily Hand......RC REPORT)