GY6 Issue By necorum (Read 1,117 times)

[necorum]

Ok, I have a 4 stroke Chuanl Longbo LB50QT-6. The engine says lb1p39qvb on the side.
www.longboamerica.com/product.php?productid=1&cat=0&page=1

I am having issue's with keep this thing running. To get the scooter started I have to put starting fluid or gas in the carb where the air intake connects. Once I do this the scooter starts and idles fine. Once I apply X amount of throttle the thing starts to die. If I remove the fuel line I have gas pouring out so I know that the carb is getting gas. Any Idea's?

Is this a main jet issue or should I just replace the whole carb with this one?

www.scrappydogscooters.com/Replacement_Parts.html
18MM CV CARBURETOR

This is a quality replacement carb for all 4stroke 139qmb 49/50cc chinese engines, NOT the junk that came with your scooter, it's got a larger venturi, accelerator pump, and quality construction. Tank, Sunl, Roketa, Vento, TNG, VIP, Baja, Jonway, JMstar, Peace, Lance, NST, as well as others. GY6 139QMB. This is usually a better unit than your stock one, so you may think about using this one instead. This carb comes with an accelerator pump which often eliminates hesitation whenver you pull the throttle open fast. Comes complete with electric choke, accelerator pump, and pre-tuned jetting for the most common settings. Unbeatable unit at an equally unbeatable price. $39.95

I have tried two different spark plugs also. Same issue. Battery is fully charged.

[Deleted]

It sounds like an air leak or tight valves. Good place to start.

[Bashan]

I agree with the venerable DW, it's probably an air leak. I suspect either a vac line is loose, the intake manifold is leaking, or you have a leak on the airbox ide of the intake system. When there's a leak there's not enough vacuum to pull the diaphragm and needle up. Consequently the scooter "bogs" when you crack the throttle. You can check for air leaks by starting the scooter and spraying judicious amounts of starter fluid on suspected parts an see if the RPMs go up. If they do that's where your leak is hiding. Alley, being the wuss that he is, sprays DW-40 and see if it quickly disappears at one spot. if so, there's your leak. Make sure all of your vac lines are secure.

[Deleted]

Jun 21, 2013 4:44:18 GMT -6 Bashan said:

DW-40

But I'm almost 50

[Alleyoop]

Wrong MOOSE BREATH, I spray water not wd-40 to find any leaks. WD-40 leaves a film Water goes WHOOSH and nice and dry. ;D

But you could fix your problem with the current carb if you want or go for a new one it is up to you. Let me know which way you want to go fix your current problem with the current carb or go for a new one. I do not want to start typing stuff if your going to get a new carb
Alleyoop

[necorum]

Sorry for the late response, busy day today.

Ok, I am def. replacing the carb. I took it apart to clean it and it was put together with screws that were not stock. (screws bigger than the stock ones). The insides looked bad. After cleaning it and putting it back together it still fails to go anywhere.

I'll also be replacing all the lines on the scooter. If this is most likely the issue with the scooter. I'll take a video of what is going on and pics of the Frankenstein carb on it once I get up tomorrow.

[necorum]

Ok, I went ahead and ordered the carb from scrappydogs and some vacuum line. I wil let you know if i have other issue's once I install.

[Alleyoop]

Good luck and do not hesistate to ask for assitance if you have any questions and or a problems.
Alleyoop