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General => Technical | How To => Topic started by: kymco_super_50 on January 02, 2013, 12:08:56 PM

Title: Fuel not coming to carburetor
Post by: kymco_super_50 on January 02, 2013, 12:08:56 PM
Hi,

Happy New Year everyone  ;D My scooter started cutting off after the fuel in the carburetor is spent. I took the carburetor off, took it apart and cleaned everything, then put it all back. Also with the air filter. The same problem; it runs fine (light brown spark plug color) until the fuel from carb runs out. What I noticed is that when I remove the fuel line (9500B in diagram) from the carb, no fuel is coming. If I blow in the line I can hear the petrol gurgling in the fuel tank. Then I noticed that removing the other line (9500E) from the edge of the carb manifold and sucking air from that line makes the fuel flow freely out of the other fuel line. Is this normal, and what could be the problem? Thanks Chris.

Kymco Super9 50AC 2008

(http://i1173.photobucket.com/albums/r588/mountainbike_chris/fueltank_zps2c34bef3.jpg)
Title: Re: Fuel not coming to carburetor
Post by: kymco_super_50 on January 02, 2013, 02:30:47 PM
Update - I found out about the operation of the part 16950 in the image (auto cock fuel) here: "....except the ZX-50 is fully automatic (need documentation though) meaning that it will only let the gas flow when the motor is (for lack of a better word) sucking for the gas."

So, could the cock fuel not operate properly or doesn't receive enough vacuum (sucking) from the carbi?
Title: Re: Fuel not coming to carburetor
Post by: naughty lee on January 02, 2013, 04:57:45 PM
Remove the pipes, fill the sink with water then nip the end of the pipe and submerge it in the water. Blow into the other end of the pipe. Look for bubbles. I would suspect a hole in the vacuum pipe.

I recently did a service on my fireblade and forgot to reconnect the vacuum hose. The bike started but cut out as soon as the carb emptied. A nipped or punctured vacuum pipe/hose will have exactly the same symptoms
Title: Re: Fuel not coming to carburetor
Post by: kymco_super_50 on January 02, 2013, 06:18:31 PM
Thanks Lee, I've just got back from dstairs and did more testing. It seems the fuel is coming into the carb just fine. I turned engine on and removed the fuel line at the carb; full flow. I should have tried this test before. Still the scooter will run on stand for one hour, but as soon as I go and run it at 20-30 mph for about 2-3 mins, it cuts off, with or without lights on. If fuel supply is not a problem, what else can it be? I cleaned carb yesterday and both jets, float, throttle valve. The only test showing a possible problem is with the auto bystarter. It shows 6.4 Ohms instead of recommended under 5 Ohm. Could the auto bystarter cause the engine to cut off after riding the scooter for 5 mins, but allow it to idle for one hour??? 
Title: Re: Fuel not coming to carburetor
Post by: kymco_super_50 on January 02, 2013, 08:00:17 PM
Update 2: I had another go riding on the roads, and as soon as I turned the corner off my street it died again.  ??? As a last resort I opened the fuel tank in case it helped create the vacuum for the fuel flow. I put it back and tried to start it; it worked again. Went for a half hour ride and worked fine - constant speeds of 40 mph - so I am now completely baffled. I'm hardly confident to go too far from home on it, so I still need to find what causes it to cut off and the next minute to work normally. 
Title: Re: Fuel not coming to carburetor
Post by: MaryK on January 02, 2013, 10:40:37 PM
Since the engine worked after opening the gas tank cap...
It may be a pinched vent hose for the gas tank.
If the tank can't get air into it, then the gas can't flow out of it.
Is #95005 the vent hose ?
Does the vent connect to a charcoal trap to keep gas vapors out of the environment & is that trap clogged ?

It sounds like you have eliminated some potential problems, so keep at it.

Scoot Safely,

Title: Re: Fuel not coming to carburetor
Post by: wordslinger on January 03, 2013, 12:29:29 AM
...didnt i just read this on another post??


...hhmmm....
Title: Re: Fuel not coming to carburetor
Post by: naughty lee on January 05, 2013, 08:35:17 PM
Quote from: MaryK on January 02, 2013, 10:40:37 PM
Since the engine worked after opening the gas tank cap...
It may be a pinched vent hose for the gas tank.
If the tank can't get air into it, then the gas can't flow out of it.
Is #95005 the vent hose ?
Does the vent connect to a charcoal trap to keep gas vapors out of the environment & is that trap clogged ?

It sounds like you have eliminated some potential problems, so keep at it.

Scoot Safely,


good advice. To absolutely check for the fuel breather pipe, I would remove the fuel cap and put some polythene over the top, securing it with an elastic band, then I'd put a small hole in the top with a pencil and take it for a ride. If the bike rides ok, it's a breather issue !
Title: Re: Fuel not coming to carburetor
Post by: Peters on January 15, 2013, 04:19:00 AM
Vacuum 101  ;)
Title: Re: Fuel not coming to carburetor
Post by: bold2000 on October 17, 2019, 09:39:36 PM
Did you find out what the issue was? I believe I have a similar issue with my fuel lines, the scooter has been standing for a while is not turning on. I have spark and the carb is clean.

Here is what happens - Bike standing for a while (6-8 hours) it starts up fine and you can drive it for about an 1 hour with max power. Than once turned off for more than 15 mins it will start up but die straight after and won't restart again unless I wait another 6-8 hours. Much appreciate your help guys, thank you.
Title: Re: Fuel not coming to carburetor
Post by: eamartin on October 17, 2019, 10:32:55 PM
What model and year is this machine?
 
Title: Re: Fuel not coming to carburetor
Post by: bold2000 on October 18, 2019, 06:46:26 PM
It’s a 2014 Agility125 with 900 miles on it.
Title: Re: Fuel not coming to carburetor
Post by: Stig / Major Tom on October 18, 2019, 08:34:12 PM
Did you try loosening fuel cap?
Posts above suggest tank is forming a vacuum.
Stig