Unplug the CDI and measure the voltage on the AC input power pin to ground on the wiring harness at the CDI connector while cranking the starter at normal speed. That means you have to jump it your car and jump the solenoid to do this. What voltage do you measure?

I think this is your CDI, right?



Yes, if you only had only one problem. But you have more than one problem. Remember you need to divide these problems up and conquer them one at a time. If you muddle them all together without trying to separate them you are only going to get frustrated and confused.

First problem: Your quad battery is not up to par (either it is discharged or defective). When you are looking at other problems such as weak spark you don't want to be taking measurements with a duff battery. Otherwise is the weak spark caused by a low battery (and low cranking speed), or is it something else? How would you know? You can bypass a weak battery by jumping it to a working car battery, so make sure you do that when doing any tests. Or fix the duff battery so that the quad cranks normally. If it needs charging then do that. If it is bad replace it (or take it back since it is new). If you leave your battery sitting around discharged it is going to be ruined in short order anyhow.

Also remember that many things can keep a quad from starting besides weak spark and a duff battery. Compression issues, valve adjustment, fuel delivery, vacuum leaks, the list goes on.... But you need good spark first. Get that working first then go on to the next problem if it proves necessary.

This is yet another problem. I think this is most minor of the three so I wouldn't let this divert you from the weak spark issue. You said originally that the starter doesn't engage with the start button. Most quads use the brake switch as a safety interlock that keep the start button from working unless the brake is applied - i.e. the brake switch is closed and the brake light is on. You changed the brake switch and now the brake light is on all the time. I suspect that your brake switch is bad or perhaps misadjusted (if it is adjustable). Your can easily verify this: Release the brake and unplug the switch - if the brake light goes out then viola, your switch is stuck closed.

 

i am getting a little confused... if the quad would at least turn over i would be able to trouble shoot it a little bit better, but if it would turn over, shouldn't i figure that first why it is not, then worry about spark/ dead battery... i don't understand what a weak spark would mean if i can;t even get it to turn over... my understanding of the process it this... if it turns over and we don;t get spark.. it would mean to that it could be a bad spark plug/ or wire, or even the CDI box (which i already replaced) but if i did have spark... it wouldn;t start.. i would then move on to a fuel issue... if i was getting spark/ fuel and still no start then i would move onto the carb... but i need to the unit to at least turn over... it did turn over and start before.. but then all of sudden it won;t turn over to even try to trouble shoot the other issues... i do know that i do not get power to the starter button when i take the controller apart and test it using a tester light... so something is not allowing power to the starter button... i pretty much replaced everything else electrical except for the entire wiring harness... which quite frankly... i am feeling that i am getting to the point of doing just that !... i do have a mechanical background and have been able to fix array of issues including rebuilding car engines.. but this one is beginning to take the cake...

as for trying to test the CDI box i do not have that sort of equipment... i never had to deal with something this so complex as to wiring.. usually i can typically find the problem with a tester light... this however is not allowing me to do so... so i would like to focus more on why it's not starting then move onto why the spark is weak and so on....

thank you for your time and commitment.

 

Ok. Let's figure out why the solenoid isn't working. You need to get 12 volts applied across the the two small wires feeding the solenoid. When that happens the internal actuating coil generates a magnetic field which sucks down on steel plate that shorts the two big screw terminals together - you have already proved this works by doing this manually.

Here is a wiring diagram of my 150cc quad:




This wiring is typical for 150cc GY6 machines, but by no means is the only method to wire it up. So lets follow how 12 volts gets hooked up to the solenoid. The battery(+) goes through a fuse. On page two it goes through the ignition switch, then on to the brake switch. When either of two brake switches are closed the brake light lights up and the same wire the lights up the brake light goes to one side of the starter solenoid actuating coil (back on page one). The other side of the actuating coil goes to the starter button, and when this is pushed this line is grounded - aplying 12 volts across the solenoid acuating coil. The solenoid goes "click", and the starter is now hooked up to the battery and turns.

Almost all quads have some sort of safety interlock to keep the quad from starting up and taking off unexpectedly. It could be a clutch switch, or a neutral switch, or a switch that says you at least have the brake on. The brake switch interlock is the most common method on quads, and that is why so much discussion has been focused on whether you brake light is working or not. Is that the method your quad uses? I suspect so, but I don't know for sure. Think back to when your quad was new. Did you have to apply the brake to crank the starter? Put it in neutral? Do you have a clutch lever? GY6 engines are fully automatic and don't have a rider controlled clutch.

What do you mean by "controller", and why do you need to take it apart? Perhaps you are referring to the starter button up in the handle bar switch assembly?

Yikes. Test lights...These things are worthless. They give you two answers: something or not. If it lights up you don't even know if that means 12 volts DC. It could be AC! Even then, there is a broad continuum between those two answers of 12 volts and nothing, and important data lies therein.

Once upon a time Test lights cost $10 and meters cost $150. I can see why anyone way back then (at least 10 years ago) might opt for the cheaper, but much less useful, test light. Today test lights cost $10 and meters cost roughly the same.

Meters will tell you everything a test light will, and so much more. Is it 12.3 volts or 13 volts DC? How is your test light going to tell you that? Is it even DC? Maybe it is AC. Is it 400 volts AC or 0.3 volts AC? Both of these important voltages are present on your quad. You may need to measure them. You can also measure continuity with a meter, or open circuits. And you can measure the broad range in between open and shorted. You can measure current, from millionths of an amp up to 10 amps. You can measure semiconductor junctions. It takes skill to use all these functions, but over time these can be learned.

So you want to change the wiring harness. Maybe that will work. If so I will salute your success. If it were me I'd buy meter instead (probably a lot cheaper too). I'd find the one wire that is bad and fix or bypass it (or whatever else is wrong). Help is available, but you aren't going to find most wiring problems with a test light.

 

What do you mean by "controller", and why do you need to take it apart? Perhaps you are referring to the starter button up in the handle bar switch assembly?

why did i take it apart? i thought that the connection at the starter button might have been corroaded or dirty... however i also used "my test light" on both sides of the switch and had no power on either side, therefore i felt that the situation had to be somewhere before the handle bar switch.

Almost all quads have some sort of safety interlock to keep the quad from starting up and taking off unexpectedly. It could be a clutch switch, or a neutral switch, or a switch that says you at least have the brake on. The brake switch interlock is the most common method on quads, and that is why so much discussion has been focused on whether you brake light is working or not. Is that the method your quad uses? I suspect so, but I don't know for sure. Think back to when your quad was new. Did you have to apply the brake to crank the starter? Put it in neutral? Do you have a clutch lever? GY6 engines are fully automatic and don't have a rider controlled clutch.

the only switches i could find was the following... left handle bar brake and this is what had to be squeezed to make the unit start.. however squeezing it no longer works.... the next switch is connected to the shifter "Forward - Neutral - Reverse" i have replaced this one.. the old one was loose and didn;t seem to do anything as the unit would start "in gear" now that i replaced it... the adjustment might be off, however there is no power to either wire at anytime. the ATV must be a GY6 cause there is no clutch and is fully automatic.

now i do get power to the kill switch but nothing after.. i think?

i have only four wires coming from the key then goes to plug whereas only the black and red wire come out.. there is no power on the other two wires at any given time.

i will print out the wiring diagram and follow it the best that i can... the thing that really brothers me is that i got this new fully assembled and ran great last year and even this very early spring.. then all of sudden. nothing! and being that the battery was bad.. my first thought was to replace the battery cause i am thinking that the battery just won't take a charge no more.. then when i put the new battery in and still nothing!!

my saga contiunes... still .. i thank you for helping me... and then i never really got one of those meters.. never really needed one plus.. i never really understood them.. i guess i am old school even tho i am only 38..

 

If your quad is wired like mine then the start button would short one side of the solenoid actuating coil (one of the two small wires) to ground. It would be nice to verify that, but (alas!) you need a meter for that (set to measure resistance). You hook one side up to the solenoid coil, and the other side to ground. Press the start button and see if the resistance drops to zero ohms.

I've never heard of a switch on the forward/reverse lever on a GY6 150cc machine. I'm not sure that means much since there are so many chinese vendors out there.

So use your test light to see if the brake switch has power on one side all the time with the ignition switch on, and power on the other side only when the brake lever is pulled. You said you used to have to pull the brake to start up the quad, so therefore your quad is wired that way, and you will need to get the brake switch working to get it to turn over.

The most common wiring scheme would be to run the switched brake light power to the other side of the solenoid actuating coil (not the side that is grounded with the start button). When you look at a wiring harness from any connector you see wires go into the taped up array with no way to follow where the wire is going. But you do have a clue - if a pink wire enters the harness it will pop out somewhere, and it will still be pink. In addition, quad vendors are pretty good at maintaining color schemes for a given function. If your quad kill switch wire in the wire harness is black with a white stripe, then it will be the same color on *all* the different kill switches. If you find a ground wire that is green, then all green wires will be ground. So note the wire color in the wiring harness for your brake switch on the load side. Does the same color wire pop out of the wiring harness at the solenoid? Does it pop out at the forward/reverse switch? Once you find the same color wire, then you can verify that they really are the same point by using a (gasp!) meter.

The kill switch is usually grounded when any of the kill switches are on, and open otherwise (test light should still show nothing) with a stopped engine. When the starter is cranking the voltage on the kill wire is really complex with both AC and DC components. I have no idea what a test light would read while the starter is turning.

On your ignition switch you should have one wire that is hot all the time, and one wire that is hot only when the ignition switch is on. You can use a test light for these two wires. The other two wires are the kill switch and ground wires. Did I understand your post correctly, and only two wires from the ignition switch enter the wiring harness? Or do all four enter the harness and only two wires have power? The latter would be the common wiring scheme.