Fuel Supply Problem
 

I have a Glow model which is having fuel supply problems. I bought it dirt cheap second hand with everything in it. The Webra motor is practically new with excellent compression. My problem is that after filling the tank, blowing a little fuel through the system with the silencer tube, and starting the motor it dies very quickely. There does not seem to be enough pressure from the silencer to pressurize the tank and keep the fuel flowing. I have checked all the filters, tubes, seals, and everything seems fine. There are no leaks from the tank either.

Has anyone please got a suggestion because this is driving me nuts!

Thanx
Englischdude

RE: Fuel Supply Problem
 

How long does it run before dying? How old is it? Do you have pics of your setup?

RE: Fuel Supply Problem
 

it literally runs long enough to burn the fuel which i manually have deposited into the carb. This means it runs like a bat out of hell for about 3 seconds and then dies!

RE: Fuel Supply Problem
 

This may sound like a stupid question, but I don't know your experience so I'll ask it... Have you tried opening the needle valve?

RE: Fuel Supply Problem
 

I'd guess that one of the lines has a pinhole in it that's preventing fuel flow, or that the tank is sitting way below the spray bar in the carb. Does the tank have a clunk line inside? Is it kinked?

How sure are you of the needle valve setting(s)? Try turning the high speed needle all the way in (don't tighten it, just until it stops!) then back it out about 2 to 2 1/2 times.

Try the needle valve setting first, then replace all the fuel lines, including the one in the tank. Maybe replace the tank too.

Let us know how it goes.

Good luck and welcome to RCU!
Dennis-

RE: Fuel Supply Problem
 

Thanks for the tips, what is for one a stupid question is for another intelligent, so dont worry!

I have tried a whole host of different needle valve settings and nothing seems to do the trick. The model is a Charly from the company WIK in Germany (now extron www.extron.net) , and has a Webra 7,5ccm motor. The silencer tube is looking a little suspect to me, there is a big dent in it and the outlet pipe can move back and forth freely inside the outer aluminium tube (dont know if thats normal, not got enough experience). If I take off the silicon tube from the silencer which acts as the pressure feed for the fuel flow and blow into this with the inlet tube for the carb crimped there are no leaks. If i uncrimp the carb inlet then the air flows freely!!

If anyone could be so kind as to help me with some more suggestions, please send me an Email under [email protected] and I will take some pics this evening and send them.

Many thanks guys from the austrian alps!
Englischdude

RE: Fuel Supply Problem
 

englischdude,
Open the NV and attatch a piece of fuel tubing, you should be able to blow through it, if not it may be plugged with debris, or old solidified castor.

RE: Fuel Supply Problem
 

I think I would try to run it with the pressure line disconnected. To see if the pressure nipple is not blocked. With the nipple blocked you cannot draw fuel from the tank. If this solves the problem replace the damaged muffler. I would replace it as a matter of course if it were me. otherwise check for blockages in the carb as another poster suggested. Good luck.

Mark Shuman

RE: Fuel Supply Problem
 

Praise the lord!

After further inspection it turned out that there were no seals between the motor and the needle valve, fuel inlet, and muffler. The plug was also useless. No she purrs like a kitten!


Thanks for all your help!!

Just goes to show I guess, when I read on ebay "goes up like a bat out of hell", I am not sure if they were talking about the plane or my damn blood pressure!

RE: Fuel Supply Problem
 

"Just goes to show I guess, when I read on ebay "goes up like a bat out of hell", I am not sure if they were talking about the plane or my damn blood pressure! "

:)

Glad you were able to diagnose and correct the problem(s). With you first description I never would have suspected missing "O-Ring" on the carb, but probably will in the future. And bad glow plugs usually show up as the engine quitting as soon as the glow igniter is removed.

Have fun with the planes.
Dennis-