Problems with TaoTao ATM50 [Carb/Throttle/Stalling] By otani (Read 2,471 times)

[otani]

Let me first preface this by saying I know nothing about engines. A friend of mine ordered me a TaoTao ATM50 (50cc GY6 Engine) from scootermadness.com a few months ago. About a month back, it started having problem. It would not start. I know nothing about engines, but I know several people who do, and we were able to narrow down the problem to the carb.

I got in touch with Scooter Madness, and they sent me out a replacement carb. I installed it the other day, and it does indeed work, but I am having issues. I cannot get the scooter to start, either electricly, or kick started, unless I put some starter fluid up the air intake first. Once it is started, I have to keep the throttle and rear brake on (to prevent the tire from spinning). If I release the throttle, it stalls. If I release the brake, it stalls. I know that it is getting gas, cause as long as I keep the brake and throttle on, it'll run indefinately, much longer than a single shot of starter fluid would last. I tried adjusting the the idle screw, but even with it screwed down to the max, it still will stall if I release the throttle. Any thoughts?

[kagetenshi]

Is the carb they sent you sealed? And what sizes are your main and idle jet respectively if it is not? They say that the Chinese scoots are notoriously lean so you could possibly need to upjet.

[otani]

Aug 1, 2015 6:58:56 GMT -6 kagetenshi said:

Is the carb they sent you sealed? And what sizes are your main and idle jet respectively if it is not? They say that the Chinese scoots are notoriously lean so you could possibly need to upjet.

Stock, so far as I know. I ordered a replacement main jet, but when I took the first carb out, to replace the jet, the heads of the screws holding the lower and upper half together were sheared off, so it was impossible to take it apart. I thought I would change the main jet with the new carb, but when it got here, I could not get the screws to come loose. I stripped one of the screws, and even tried just using pliars to grip its outter edge. The screws WILL NOT move.

[kagetenshi]

You could try taking a hacksaw/dremmel and running a groove across the head of the screww and using a flat head to gently back it out. I had the same issue with 2 carbs and ended up taking it to a mechanic and giving him $10 to get it out rather than causing myself a headache. I would go ahead and buy some tougher screws though as the ones they ship those carbs with are made of soft crappy metal.

[kagetenshi]

As for the jetting, I know that no2 scoots are created equal but my taotao VIP 50cc ran like a dream after I put a #82 main in.

[otani]

I bought a #80 replacement. Just gotta get inside the carb.

[kagetenshi]

Pb blaster or Deep Creep could help make the job easier. Or if you can't get it out the other way you could always drill it out. Just be careful with the threads.

[otani]

I have the carb out, and I used a dremel to cut a slot, but when I tried to use a flat head, it just made it worse. I was however able to use a pair or pliars to "break" the screws lose, then use a normal screwdriver to get the screws out. I have it open, and have changed my main jet. Is there anything I should be looking for inside the carb that could be causing the issues I described above?

[kagetenshi]

I would check for deposits in the jets. Also, the screws don't have to be in tight. Just snug. If the sputtering continues you could try adding some Seafoam to the gas tank and running it through. Use 1ounce per gallon. Other than that you should be good.

[kagetenshi]

Also, make sure the idle air/fuel screw is about 2 to 2 1/2 turns out (counter clockwise) from all the way in.

[Alleyoop]

Here follow this procedure to adjust the carbs fuel mixture:
NOW BEFORE YOU DO THIS TURN THE FUEL RATIO SCREW CLOCKWISE until it stops do not force it. THEN turn it COUNTER CLOCKWISE 2 turns since it is summer time.
Now when it starts lower the IDLE USING the IDLE SPEED SCREW the one with the SPRING under it so THAT the REAR WHEEL is NOT SPINNING.

At this point the motor should still be running. IF so now you can adjust the FUEL RATIO MIXTURE follow this step by step procedure:
scooterdoc.proboards.com/thread/1499/4ts-carb-tuning

[otani]

Hooray! I got it working!!! I think the issue was it was getting too much air. I don't know what made me think to do so, but when I pulled the carb, I also decided to take off the intake manifold, and I noticed there was some really big tears in it, between in metal collar, and the carb output to the cylinder. I brought it in, then tried to super glue it, and electrical tape it. I then noticed that on the inside, where was still some large gaps, so I took some hot glue to seal it up. When I put the manifold and carb back in, I made sure it was super secure. And sure enough, it fired up.

[Alleyoop]

GOod job YES, to much air not enough fuel running LEAN that is why it needed a lot of throttle to keep it running. Also it could happen the other to RICH, foam filter clogged not letting enough air in, but if to rich is would sputter and bog when given throttle.
Alleyoop

[kagetenshi]

Thats why I leave it to the pros. I AM still fairly new to these things as well...