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OT: Chinese carburetors

So I have this scooter, a Kymco, and it quit on me while shopping with it. Worked fine, parked it, came back with shopping bags, and it does not start. Nothing, nopes, no nothing.

So, somebody with a van helped me, the shopping bags, and the scooter home.

Seemed not too difficult a problem... After all I have repaired every thing before. Now, simple test:

1) I have a spark. 2) I have fuel. 3) fuel makes it into the cylinder (it is a 4 stroke). 4) air makes it into the cylinder. 5) it does suck a vacuum when starter motor turns (or kickstart used), this opens the fuel valve. Recharged the very small 12 V battery, 4 Ah only, good for 1 minute starter motor with cold thick oil... 1 minute trying, battery empty again, only once a 'sneeze' from the engine.

Took out the carburetor, checked the automatic choke, had it on the bench, it worked.

Now the word 'Chinese puzzle' is appropriate for this scooter, as I had, to disconnect the auto choke ('auto bystarter') take aways the side panels, what required taking away the seats, the rear seat, the whole ** thing, just to loosen a connector, but anyways, all to no avail.

It ain't running!! I am now recharging that battery again, but it says max .5A charging, so that will take all day.

One thing is strange, I thought I smelled ozone, but the CDI unit seems intact, and I do have a spark, when testing that spark plug outside the cylinder.

Any suggestion? I hate to spend $$$$ to have it picked up by the dealer in an other city, where it then probably will work, and get charged 250 Euro for a new //

Reply to
Jan Panteltje
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"Jan Panteltje" schreef in bericht news:gnosea$12f$ snipped-for-privacy@news.datemas.de...

Two things come to my mind.

1 - Ignition timing. Wrong timing can cause a lot of problems, though FAIK timing on those Kymco's is not adjustable. 2 - Spark power. A spark plug that seems to do well in free air may not do so well while under compression.

So when nothing can be found on he carburetor, the ignition system becomes prime suspect. This includes the sparkplug and the bobine but also the timing mechanism. I was told this to contain some electronics but I did not disassemble an engine that far yet. I'm after the workshop manual for quite some time now but to no succes.

petrus bitbyter

Reply to
petrus bitbyter

Somebody recognized Jan, replaced half of gasoline with water ;-)

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
 I love to cook with wine     Sometimes I even put it in the food
Reply to
Jim Thompson

Does it have compression? The symptoms aren't consistent with a whole bunch of "lost compression" problems, but a stuck valve would do it.

Can you get starting fluid over there? If it won't work with a squirt of starting fluid then it ain't the carburetor! Note that you don't have to replace the carburetor to try the test -- just give it a squirt in the intake port & try it out.

--
http://www.wescottdesign.com
Reply to
Tim Wescott

before.

will take all day.

intact, and I do have a spark,

Assuming no one tampered with the gasoline while it was parked I would have to agree that the timing could be off. Is it possible when you stopped it, that you "clutched" and stalled the engine to stop it, and perhaps the flywheel (possibly part of the timing mechanism) was loose and slipped its position? Usually there is a steel key inserted into the end of the crankshaft to set the position of the flywheel. If the flywheel is loose, all can be fine until the engine is abruptly stopped, in which case the key or the flywheel (if soft alloy) may deform and the timing will get out of synch. I assume you have electric start, so on start up, the same could occur if engaging starter while in gear.

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Use only Genuine Interocitor Parts" Tom Servo  ;-P
Reply to
RFI-EMI-GUY

Or, being Chinese, someone may have left the key off entirely. If it's a tapered shaft it would take a while for things to work loose.

--
http://www.wescottdesign.com
Reply to
Tim Wescott

On a sunny day (Sat, 21 Feb 2009 15:46:55 +0100) it happened "petrus bitbyter" wrote in :

It is a pickup coil, I think it can be mechanically moved, but am not sure. But a bit unlikely that that should just change when it is standing still.

That may well be the solution. I will have to play a bit more with the spark tomorrow when it is light if the second battery charge does not help to start it.

Good idea, I was thinking maybe it sparks through the HV cable to the metal, it is difficult to see, as the sparkplug is shielded by an other air flow cover when in.

I have the service manual, it is a Kymco Agility 50, I can email it or give you a link if you want. I got if from the Kymco site some years ago, it is in English,

183 pages pdf with pictures and all technical data, except of course why it does not start.. I followed their fault finding 'tree', that is why I took out the carb and choke...
Reply to
Jan Panteltje

On a sunny day (Sat, 21 Feb 2009 10:16:07 -0600) it happened Tim Wescott wrote in :

Yes it has compression, you can feel that when using the kickstarter.

Now, here the Chinese have some more puzzle for you, the carb intake goes to a huge tube, and that tube goes to a big compartment, with a paper type air filter in it.... I do not have starting fluid, but I could remove the air filter. To get to the carb air intake, you have to remove the other end, at the cylinder, lift it, and then pull it out of the air tube... ^ lift to remove carb | tube1 tube2 tube3 / ==[carb]========[airfilter compartment]=======air intake || \\ \\cylinder \\ \\

Reply to
Jan Panteltje

On a sunny day (Sat, 21 Feb 2009 08:03:38 -0700) it happened Jim Thompson wrote in :

I am not too worried about sabotage, first the tank is locked, second you could not even find where to put the fuel or water, and third you were too far away.

Reply to
Jan Panteltje

On a sunny day (Sat, 21 Feb 2009 12:30:43 -0500) it happened RFI-EMI-GUY wrote in :

Jim seems to have ....

It is an automatic transmission, I stopped it with by turning the key to off. I agree the timing could be wrong. The electronics is potted... pickup coil position? I think the flywheel pin is still intact.

Reply to
Jan Panteltje

"Jan Panteltje" schrieb:

intact,

Some ideas: - the sparkplug is soaked with gasoline. Pull it out and wipe it clean. - spark-plug or wire is damaged. - the CDI is damaged and does not provide the correct timing or enough power. If it suddenly stopped working, it's probably not the carburetor.

bye, Dan

Reply to
Dan O.

Try it with a new or a known good battery !#

0.5A Charging says its either shot, most likely, or fully charged, which your experience suggests it isn't ! 
--
Best Regards:
                     Baron.
Reply to
Baron

Is 0.5A all it will take, or is it labeled "charge at 0.5A max" ??

If 0.5A is all it will take, you are right, it's a croaked cell.

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
 I love to cook with wine     Sometimes I even put it in the food
Reply to
Jim Thompson

before.

will take all day.

and I do have a spark,

Fuel air spark is all you need so . . .

Do you have a service manual?

Spark coming at the wrong time Timing light or Ohm meter if it has points (or obvious physical problem like mechanical link stuck in full advance if it has a mechanical advance)

Fuel contaminated Rig temporary fuel supply with known good fuel

Fuel mixture way off No good safe ways to test that, but you can restrict the air or fuel and see if it tries to start. Carb float could be sinking or float valve could be sticking, allowing excess gas to flood cylinder when engine is off.

Compression too low Compression gauge (bent valve stem or stuck valve or broken valve spring, broken ring(s), etc..)

Reply to
default

On a sunny day (Sat, 21 Feb 2009 21:27:06 +0000) it happened Baron wrote in :

It is written on the battery: .5 A max charging. the regulator on the scooter is also specified like that. It is a very small sealed lead acid, about the size of 2 packets of cigarettes, want to keep in in one piece :-)

Reply to
Jan Panteltje

On a sunny day (Sat, 21 Feb 2009 14:31:34 -0700) it happened Jim Thompson wrote in :

It is labelled that way. The thyristor controlled regulator is also specified that way.

Reply to
Jan Panteltje

On a sunny day (Sat, 21 Feb 2009 16:40:28 -0500) it happened default wrote in :

Yes.

No points, pick up coil with potted electronics ... It says it has a thyristor in it, that is all I know :-)

Possibly, but why just stop like that, no prior indication of 'sputtering' was just doing max speed no problem. Was gone for maybe 45 minutes in the shop, fuel does not go bad in half an hour, seems unlikely.

I will try that tomorrow.

I had the carb on the workbench, diafragm seemed OK (inspected with magnifying glass, fuel level seemed OK, plenty of fuel there (all over the workbench when I turned it over, was pure gasoline, evaporated right away, if any water it should have stayed.

mmm, I feel compression with the kick starter. Valves normally make noises when defective, or not adjusted right, no such thing. I am beginning to think some flash over in the potted electronics, or perhaps HV cable, as that would explain why I smelled ozone, twice.

Reply to
Jan Panteltje

Wow that sounds like a very small battery. Particularly if it is also powering a starter motor.

--
Best Regards:
                     Baron.
Reply to
Baron

"Jan Panteltje" schreef in bericht news:gnpel2$59k$ snipped-for-privacy@news.datemas.de...

The one in my backyard is a Vitality 2T and has a two stroke engine. Don't know whether it differs much or not (except for the engine of course.)

My e-mailaddress is valid once you removed the Dutch spamtrap.

petrus bitbyter

Reply to
petrus bitbyter

before.

will take all day.

intact, and I do have a spark,

Make sure you have a blue spark on the plug and the plug is dry with carbon removed from the ceramic.

If that fails, the carb most likely has a plugged jet. when this happens, you won't get much vapor in the jug, over do it with the choke and you'll simply flood it with wet gas.

Simply test for this, pull the plug, dry it out, make sure there is something wet in the jug like gas. Reinsert the plug, if you get a couple of ignitions and it stops. you have a jet problem in the car.

Forcing a back fire is a good way to clean out a plugged jet. :)

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Reply to
Jamie

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