|
|
Post by scooter on Feb 28, 2015 14:27:24 GMT -5
I have a 2013 50cc Bintelli Taizhou Zhongneng Motorcycle Co. Sprint Bread 50 GY6 here.
Idles for a few seconds, then dies. Any attempt to give it gas kills it. Will start again after waiting for a minute. Seems to be flooding.
Has spark, lights work, cleaned the carb, adjusted the valves. Changed the gas out. Fuel seems to flow to the carb fine. Tank is vented well. Fuel air mix is capped but idle is perfect until it dies. Will rev high if allowed to sit for a while, then slows down and dies after a few seconds at any throttle position.
My only clue is that the diaphragm appears to have been pinched by a previous "mechanic". I didn't see any damage to it, and it went back in okay.
I plan to order a new carb in case the diaphragm or the enricher is bad. Does that sound about right?
|
|
|
|
Post by lain on Feb 28, 2015 16:21:27 GMT -5
Does fuel flow from the carb through the intake and into the combustion chamber well?
A tiny hole in the diaphragm can make a big difference I would think in such a small engine.
I'm no pro but it sounds like when you start at first the mix is okay right from start, but after the engine sucks up the mixture it changes and becomes a bad mix and the engine cannot use it to keep going. It running at higher revs if it warms up sounds like it may be able to run that high because the vacuum pressure is sucking in enough to offset it some, but I would think it would still be running bad. Have you checked the plug after warmup when it dies?
|
|
|
|
Post by scooter on Feb 28, 2015 17:18:47 GMT -5
Does fuel flow from the carb through the intake and into the combustion chamber well? A tiny hole in the diaphragm can make a big difference I would think in such a small engine. I'm no pro but it sounds like when you start at first the mix is okay right from start, but after the engine sucks up the mixture it changes and becomes a bad mix and the engine cannot use it to keep going. It running at higher revs if it warms up sounds like it may be able to run that high because the vacuum pressure is sucking in enough to offset it some, but I would think it would still be running bad. Have you checked the plug after warmup when it dies? The plug is black but not wet. Looks over rich. You can't rev it unless you let it sit for a bit. It's as though there is one "shot" of fuel and then it's done. A few seconds at higher rpm or several seconds at idle. Either way the ending is the same. The engine loses rpm and dies. I can get it to idle again after waiting, say, 30 seconds or a minute or so. It won't rev up unless it sits for several minutes turned off. Just a WAG that maybe the diaphragm isn't opening up properly. I don't really understand how it works yet, but I assume it needs to open to let more air in. |
|
Sophomore Rider
Currently Offline
Posts: 137
Likes: 24
Joined: Jul 6, 2013 21:27:28 GMT -5
|
Post by mopojo on Mar 1, 2015 17:26:30 GMT -5
If the air intake is covered say 1/2 to 3/4 does the engine run better? Blocking most air intake?
|
|
|
|
Post by scooter on Mar 1, 2015 22:27:52 GMT -5
If the air intake is covered say 1/2 to 3/4 does the engine run better? Blocking most air intake? I don't know. I didn't try that. It ran great but just could not stay running, as though it had run out of gas. Having to wait before starting it again was a clue that it might be flooding. |
|
|
|
Post by lain on Mar 1, 2015 22:46:56 GMT -5
I think you should get a new diaphragm. Or a newer, possibly better carb? Take a look at rcq92130's post here: itistheride.boards.net/thread/7374/bogging-on-takeoff?page=5&scrollTo=87359It explains a bit of the carb. Might give you a better understanding as to what is going on. I would think that if there is a tiny hole in the diaphragm that it would cause it to not function properly, doesn't really matter if it's running too rich or lean because it is not a controllable condition and it will get worse. Not that it can really get worse than not running! lol |
|
Sophomore Rider
Currently Offline
Posts: 137
Likes: 24
Joined: Jul 6, 2013 21:27:28 GMT -5
|
Post by mopojo on Mar 2, 2015 11:59:50 GMT -5
bruppppp
|
|
Sophomore Rider
Currently Offline
Posts: 137
Likes: 24
Joined: Jul 6, 2013 21:27:28 GMT -5
|
Post by mopojo on Mar 2, 2015 12:01:23 GMT -5
If the air intake is covered say 1/2 to 3/4 does the engine run better? Blocking most air intake? I don't know. I didn't try that. It ran great but just could not stay running, as though it had run out of gas. Having to wait before starting it again was a clue that it might be flooding. Maybe it is a cheap/effortless way to tell if it is running lean or rich? May be worth a stab.... |
|
|
|
Post by JerryScript on Mar 2, 2015 19:34:17 GMT -5
The diaphragm opening up allows more fuel in, not more air. If your plug is black, you are running too rich, too much fuel. I bet you have to keep your idle high to keep it running. If so, that is because increasing the turns on the idle speed screw actually opens up the buttefly, allowing more air in, which you need due to a too rich condition. Try turning your a/f screw in 1/4 turn at a time, waiting a full minute between each change. Once you get to the highest idle speed you can achieve, turn the a/f screw back out 1/4 turn. Now set your idle speed screw to the highest idle you can without causing the wheel to turn (or if you have an RPM gauge, set it to around 1700rpm).
|
|
|
|
Post by scooter on Mar 2, 2015 22:57:34 GMT -5
The diaphragm opening up allows more fuel in, not more air. If your plug is black, you are running too rich, too much fuel. I bet you have to keep your idle high to keep it running. If so, that is because increasing the turns on the idle speed screw actually opens up the buttefly, allowing more air in, which you need due to a too rich condition. Try turning your a/f screw in 1/4 turn at a time, waiting a full minute between each change. Once you get to the highest idle speed you can achieve, turn the a/f screw back out 1/4 turn. Now set your idle speed screw to the highest idle you can without causing the wheel to turn (or if you have an RPM gauge, set it to around 1700rpm). It idles very smoothly with the screw all the way out, not touching the throttle at all. It just dies, as if the bowl had run out of fuel. Adding any throttle via the screw or the the throttle cable just makes it die faster. I cleaned out the carb with spray in all of the holes but it makes me wonder if the float hole is letting fuel in. Maybe that's why I have to wait to start it again. Perhaps fuel is slowly filling the bowl again. If I try to open the throttle while cranking, it won't start. EDIT I took the bowl of and the plastic bowl has a metal tab. I also see fine particulate matter in some places, junk from the fuel tank I suppose. I'll try cleaning it again. I know Alley or someone posted how to check and adjust the float so I'll try that too if I can find it. SECOND EDIT. Found yellow gunk in bottom of bowl. Reminded me of sulfur. Cleaned it out and cleaned all the holes and jets again. Now running great on the stand. Must have got junk from the gas tank. The gas was yellow that I took out. It looked like Gatoraid. I think the old gas might have had phase separation as shown on the right in this online picture.  I'm going to see if I can rinse it out and make sure it's clean. It looks like it's going to be a real pain to get the tank off the bike. Maybe I could just turn the bike upside down.  UPDATE: Just an update on this old thread. The problem was bad gas gunking up the carb. I flushed and cleaned the gas tank and carb then it ran. Thanks, everyone. |
|
