The spark is derived from actually 3 things, voltage from the stator (if it is AC) the CDI and coil. Also there is what is called a pickup coil or pulse sensor in the stator area that sends a time message to the CDI as to when to fire.
thescooterprofessor.proboards.com/index.cgi?board=gele&action=display&thread=248Now we have testing specs in the tech section on what to test for and what voltages to expect. People a lot of times just start buying parts and putting them on in hopes of curing the problem when it could be something as simple as a bad connection and since you got one jolt of voltage and now have none it leads me to believe just that.
So with that said I'll ask you if you have enough of the plastics out of the way to expose the CDI and coil? Even the spark plug cap connetor that slips on the spark plug can come apart in a way that it will not spark or randomly do so, it's easy to take apart and check.
Now I'll ask you the following wire colors and what they go to and we'll see if they match the common 150 GY-6 chineses scooter? If so then we'll start the journey to find the problem.
Ok so here's a list of wire colors and where they go on a typical chinese scooter from the stator to the coil;
red/white = stator pick up coil wire going to the CDI
black/red = AC feed wire from stator to CDI
green = ground
black/yellow = CDI feed wire to coil
black/white or gray/white = CDI engine kill wire
So the first thing I would check is the spark plug boot or cap, again you mentioned a momentary spark and here is a tech PDF from the tech section breaking down the coil and it's parts;
.jr-richscooterdoc.com/Help_new_coil_instructions.pdf" rel="nofollow" target="_blank">
.jr-richscooterdoc.com/Help_new_coil_instructions.pdfIf you find nothing there then look at the two wires feeding the coil should be black/yellow and green= ground. Check the wires very carefully for a bad connection and make SURE the ground wire is grounded well and I would recommend checking it out with a ohm meter. Poor grounds are very common on Chinese scooters and have been a source of many headaches for many.
Next check each wire and connection on the plugs that plug into the CDI again poor connections and grounding will and can cause a lot of problems.
Especially p[ay attention to the CDI engine kill wire the black/white or gray/white wire. You for sure need to ohm this wire and here's how.
(1) unplug the plug with the gray/white or black/white wire
(2) turn on ignition key switch
(3) make sure emergency engine kill switch is in the run position
(4) put one lead of ohm meter to ground and the other to the gray/white or black/white wire and set your ohm meter on say the 20k setting
You mentioned you had a side stand safety switch, if this is so then most of these switches are a simple on/off switch and it will most likely have a green = ground wire and again the same gray/white or black white wire also. To check out this switch along with the engine kill wire you must have the side stand in the up position.
So with the key on, emergency kill switch in the engine run position and the side stand up you should get NO ohms resistance or no continuity if all is well.
If you have resistance then either one of these switches is bad or the circuit wire is grounded out by touching ground in the system somewhere?
To test each switch just simply leave you ohm meter leads hooked up and check each switch one at a time.
(1) key switch off = full continuity
(2) emergency engine kill switch in off position = full continuity
(3) side stand safety switch in down position = full continuity.
Now of course do one switch at a time.
If you find a problem in this circuit the CDI will not send voltage to the coil and thus no spark.
Let us know what you've got and we'll go from there.
JR
..BAD TO THE BONE..
