Restoring a Trashed 2013 Jonway - HELP

[yammer]

I left my scooter with a friend when I was assigned overseas for a year.  When I returned he had literally trashed my good, low mileage scooter.  I ordered a new Carburetor Kit off Ebay.  The vendor assured me that it was correct for my 49cc scooter.  When I received the kit it had a new elbow between the carb and engine and a conical air filter which attached directly to the carb.  The new elbow however as only one inlet, while my old elbow (same size) had two inlets.  I decided to use my old elbow as I still had the two lines to deal with.  When I started up the scooter within 3 minutes there was gas pouring out of the new filter and the engine shut down.  Not knowing where the gas was coming from, I removed the gas supply line to the carburetor.  THIS DID NOT STOP THE LEAKING THROUGH THE AIR FILTER.  Only when I pinched off the line which ran from a metal circular connector below the gas tank, did the leak stop.  The vendor now suggests that I simply block this line and use his one inlet elbow.  He has yet to explain to me why the stock scooter had two lines running to the elbow, and what do I gain or lose by simply blocking off this line.  As my scooter ran fine with the two line (stock) configuration, leaking profusely now implies that the circular apparatus immediately below the gas tank has failed in some way.  Any guidance and/or information would be gratefully appreciated.

[pinkscoot]

Sounds like you have the hoses crossed. The part below the tank is a vacuum petcock. If its letting gas through without vacuum applied then it's bad. If the carb is just pouring gas out it probably has a stuck float valve. Pictures are always helpful to get this straightened out.

[yammer]

Finally, someone who seems to know what they are talking about.  Thanks Pinkscoot.  First, I do not have the hoses crossed.  As usual, I took a photo of the engine compartment before I started my work and then checked after installing the new carb to see if I did everything properly (i.e. as before).  As requested I have attached two photos which I think clearly delineate my problem.  The first photo shows the vacuum petcock (?) with two lines running from it.  The top line (right side) is the fuel supply  hose which goes to the fuel filter and then to the carb.  The bottom attached line runs to the elbow after the carb - just before the engine.  This is the line that seems to be flowing fuel and which I had to pinch off to stop the leak.  You can see part of the tool I used to pinch off the line in the photo.  The second photo shows the old elbow I am using with two hose attachments because the newly purchased elbow only has provision for one hose attachment (looks exactly same size but with only one inlet).  The carburetor vendor wants me to now simply block off the line from the vacuum petcock and use his one inlet elbow.  Should I do this, or should I replace the defective(?) vacuum petcock and return to the original configuration?  If blocking this line is OK, then why did the manufacturer have the line and its routing in the first place? Do I lose anything by blocking off this hose?

With gas constantly flowing through the top hose on the vacuum petcock to the elbow,  it appears to have filled up (flooded?) the engine, flowed back through the carburetor, and out through the new air filter and on to the ground.  I do not know if this flow through the carburetor means that it has a stuck float valve,  but it is a newly purchased carb with less than 5 minutes of running time on it.  The scooter did seem to run OK for a couple of minutes before it apparently got "drowned" in fuel.  It is not surprising that the carb vendor has not suggested the possibility of a stuck float valve. If you are saying that fuel would not flow back through the carburetor to the air filter unless the float valve was stuck (open?), then it appears I have two problems: a defective vacuum petcock and a defective carburetor.  Do you know where I can purchase a new vacuum petcock?  The carb vendor hasn't even named this part and seems not to sell anything but carbs.  Again thanks ever so much for your help.  PS, I went to UNC.  Go Tarheels.

[yammer]

Sorry I clicked on the wrong photo.  Here is the one with the Vacuum Petcock.

[bullybike]

yea those petcocks do that. most 9f those cheapo carbs have to be cleaned and rebuilt before use it seems quality control=0 for chinescoot

replace petcock run vacuum line to intake manifold elbow.
also replace breaks shoes anc clutches maybe and belt.
also check valve stems for softness.
cheers

[aeroxbud]

You petcock is bad. No fuel should come out, if the engine as not turning. Creating a vacuum.
But the carb should also stop the flow of fuel. The job of the float, is to raise up as the fuel level increases. When the bowl is full the pressure on the needle valve, should stop any fuel getting past.

[GrumpyUnk]

If the 'rubber' diaphragm in the petcock is damaged, it can allow manifold vacuum and/or gravity to pull fuel into the elbow and thence the intake poet, possibly filling it and overflowing back through the air inlet side. The rubber can get brittle with age and crack or leak. A standard air cleaner assembly would be peeing gasoline out next to the rear wheel, a pod style, who knows.
A new vacuum petcock should fix that problem.
The second port on the elbow is usually used for some emission control device, mostly diaphragms that divert/do not divert airflow into the exhaust stream(a common usage). If you no longer have that diverter valve, lack of a second port is not a problem. Many are plugged over time with no noted effects.
tom

[yammer]

Thanks guys. Ordered a new vacuum petcock. Should be here tomorrow. Now next problem: My friend also laid the scooter over on its side trashing the air box assembly. So I ordered a new one. The new "universal" air box assembly when bolted up does not reach the carburetor! The 1 inch rubber supply tube is about one inch short of reaching the new replacement carburetor intake port. There appears to be only one way to mound the air box - with two bolts at the bottom into a bracket on the scooter. Am I doing something wrong? Is there a different assembly I should be getting or is there some sort of extension which will allow the supply hose to reach the carb? Any help would be appreciated.

[yammer]

Also, something I forgot to ask. With all the broken items on my scooter, there are a number of small rubber hoses (vacuum lines?) which are now just dangling. Where can I get a schematic (diagram) which will show me how to hook up these lines. Some probably connect to one another, some may have been connected to ports on the scooter I can not now identify. Also the correct routing of these hoses would be helpful. Sorry for all the questions but you can not image the mess my so-called friend left my scooter. Again, thanks for any help.

[GrumpyUnk]

You may find a diagram label on the engine or frame. It will be less detailed than you want. Most scooters can run with only the vacuum petcock connected to intake vacuum. The other things, PAIR - pulse air injection, fuel vapor storage, and I don't know what all seem to be 'add ons' that don't affect how it runs to a noticeable degree, UNTIL the vacuum lines get disconnected without being plugged, leading to leakage, lowered vacuum(causes petcock to not work properly or intermittently), and poor startup/idle control.
Plug all the leaks, or the ports to the intake & carb unless you can get a good diagram/schema.
tom