Hello guys, new guy here trying to figure out whats going on with my little buggy. First off, I am a small engine mechanic...it's what I do for a living, however, this little engine has me stumped. I bought this buggy from a friend who said it didn't run, so I got it on the cheap. I thought having no spark would be a simple and relatively cheap fix. Well, after month of online research and trying to understand how the ignition system works, I have swallowed my pride and now I am asking for help.

What I have...an off-brand Chinese buggy. It's a "Mountaineer RTV-150" with a GY6 150cc motor. The cart has VERY low time on it. Heck, the original engine oil is very clean still.

After all my effort of research, I have troubleshot this thing to my whits end. I have replaced the coil and the CDI unit to no avail. I have ruled out any kill switches and confirmed it by removing the kill wire from the CDI box harness. I have a brand new CDI unit and a known good used ignition coil from another project I fixed earlier in the year.

I am thinking of replacing the entire ignition system....harness and all. The motor has an 8 pole stator and from what I understand, most of the GY6's came with a 6 pole stator.

Here is my question.... if I get a 6 pole stator and matching flywheel found on e-bay ad #380175068973, will my rectifier still function properly? Or does the rectifier have to have the 8 pole stator?

One more question....where can I get a complete ignition wire harness for this engine? The manual that came with the buggy does not have the correct wires or wire colors going to the CDI unit....it looks like it's the incorrect diagram.

Guys, my apologies. I know this has been discussed before, but I have done everything that I have read on this and many other forums to diagnose the problem, but I still can't figure it out without throwing parts at it. (which looks like I'm about to do.

By the way, the brand on the side of the GY6 motor states "YONGHE"......lol.

Thanks for any help,

~Joe

There is a magnetic pickup coil that senses the magnet on the fly wheel passing underneath it to create the spark trigger. Measure this line to ground - It should be less and few hundred ohms. The CDI is either AC or DC powered - If there is a dedicated black/red wire coming from the stator to the CDI, it is AC. If it is DC powered, turning on the key will supply battery voltage to the CDi. Use the diagram below to trace your CDI wires and let us know what you find.

i see pghruby gave you some info so i edited this.
there was a member here that had the YONGHE engine and it had the DC cdi.
he called it the mountaineer RTV-150 but thought it was the Sun Right RTV-150

pud

Pghruby, thanks for the reply. I remember checking ohms early in my troubleshooting, but for some reason I think it was good. Let me get that info and I will get back here with results.

THANKS!!!

~Joe

Ok, just got in from checking it. Here is what I have.....

Black wire with red stripe (charge stator inside the flywheel).....205ohms and without a peak voltage meter, I am reading 26.5 AC volts.

Blue wire with yellow stripe (trigger stator outside the flywheel)....142ohms and less than a 1/4 volt AC.....that's around .201 of an AC volt.

Keep in mind, this is read from a pretty fast digital voltmeter, so take it from there...I'm sure it's not correct. I can't find anyone that has a peak voltage meter that I can borrow and I'm not going to spend the money on one.

Also as you read above, this is a confirmed AC driven CDI unit. There is no DC voltage going into the CDI harness anywhere.

What next?

Thanks for your help and your time gentlemen.

~Joe

So, you have the trigger and CDi power.

1. What about ground to the CDi?
2. Is ground DISCONNECTED from the kill signal pin?
3. When cranking the engine, do you get any voltage spikes out of the CDI destined for the coil?
4. Is the coil source from the CDI making connection at the coil?
5. Is the coil grounded at the green marked lug?
6. Has the spark plug been replaced?

With what you have already checked and what I am asking above, that is the entire ignition circuit.

#1...ground from the pin on your attachment to the bare frame is confirmed
#2...I removed the pin completely out of the CDI pigtail, so a kill circuit is non existent
#3...Lemmie check that tomorrow
#4...I made a direct connection out of the CDI pigtail, so yes it is a good connection
#5...i wasn't aware that was supposed to be a ground....Check that tomorrow as well
#6...yes...brand new sparkplug. I can hold it in my hand with my other hand grounded to the motor and I don't feel a thing.

How does the stator coil(s) ohms look? Voltage wise, is that in the ballpark?

Will update tomorrow sometime. Thank you sir!!!

~Joe

The black/red wire should be closer to 500 ohms, but I do not want to lead you into replacing the stator until the rest of the system is checked. I see too many people throw parts at a problem and create more...

There are plenty of sources for 6, 8 or 11-pole stators, but your flywheel must be matched to the number of poles on your stator. You will benefit by staying with 8-poles unless you want to do a rewire to get 11-pole capacity (like me).

Very good. I'll check up on # 3 and #5 tomorrow and check back. I think I will eliminate the ignition harness from the buggy harness. This way it will rule out a broken wire, shorted wire or loose connection somewhere.

Until tomorrow, as always, thanks again!

~Joe

Ok, well, I eliminated the entire ignition harness from the rest of the chassis harness. I wired it exactly as per attached image and still have nothing with either my old or new CDI unit.

As promised, I came up with the following....

#3....no voltage spikes. Well, there is....sorta. There seems to be about .021vac coming out of the number 2 pinout that goes to the ignition coil.

#5...this is a confirmed ground, but like I did with eliminating the ignition harness, I made my own ground and took the chassis harness out of question.

..........sigh......still no spark.

Time for new stator - It will come with a new timing pickup. Although the voltage you were getting out of it wasn't that far out, the resistance is low. Most likely it is not producing sufficient amperage to drive the coil. Make sure you order a GY6 flywheel puller at the same time if you do not have one.

That's about what I thought. I am now looking for one on E-bay. Found one on the cheap for under 50 bucks with the stators (charge and trigger) and flywheel. It seems the 8 pole stators are not used as widely as the 6 pole.

Will order it tomorrow with hopes of having it by the weekend (the seller lives close).

I didn't have the "correct" puller, but I did have one that worked quite well and got it off with no problems. Speaking of flywheels, what are the chances of the magnets breaking inside the flywheel? I just got thru working on a Polaris with no spark that had a broken flywheel magnet. On the GY6 flywheel, you can't see the magnets. Gonna have to check them with a handful of BB's. Oh cool....something else to check that I didn't think of. I'll check back.

Thanks a bunch gentlemen!!!

~Joe

Well, the new stator is on it's way. I opted not to get the flywheel because I'm pretty sure it's ok. The BB test went well with 8 separations, so I'm about 95% it's good to go.

I hope to get the stator in buy Friday, but it's looking more like Saturday or possibly Monday.

~Joe

Ok, got the brand new stator in and installed with absolutely ZERO luck. No spark, zip, zero...nodda. Tried both old and new CDI boxes and both old and known good used coil and STILL, nothing.

Looking at this pic that pghruby posted.....


I manually wired up the CDI box exactly with no luck. So, back to looking at the harness, I find something strange. The pigtail on my buggy that plugs into the CDI box...reference #3 is a green wire and is a solid ground with reference #4 being open with no wire at all......whereas the above pic shows to be exactly opposite. The same goes for #5 and #6.....both exactly opposite.

So, now that i hooked them up this way (incorrectly or correctly) will it hurt the CDI? I mean, I have a barnd new CDI box I got from the dealer for this buggy, so I would think it would work, but unless I hooked it up wrong,it may have trashed it.

As far as ohms and voltages of the new stator.....

The charge coil I get 430ohms and about 70vac

The trigger coil I get about 130ohms and about .105vac.

Dunno what to do now other than buy another CDI box and confirm the hookup somehow. As for now, I'm gonna ask a friend if I can use his buggy (same engine) to test my coils and CDI boxes.

This is getting ridiculous.

the cdi diagram pghruby gave you is the correct diagram.
now from the way i understand it the ground could go on no.3 or 4
because they are tided together inside of cdi.
now 5 or 6 has to go like the diagram.red/black power wire from staor on 6
kill switch on 5
by any chance could have you or the previous owner had the wires out of the plug and put them back wrong.

that might be your best bet is to try a friends cdi,maybe there was some damage done if power wire was in the wrong place.
also maybe look at his cdi wire hook up if you can.

pud

Pud, thanks man. Yes, it is very possible that he installed the wires incorrectly. I know he had it apart and was messing with it. And his mechanical ability is somewhat shotty..... so yeah.

As for the #3 and #4 pins, I ohmed them out and on both CDI's, they are connected together. But as far as ohming out CDI pin to CDI pin, they look very close to one another. Now that does not tell me anything I know, but it was worth the 2 minutes I wasted doing it. I should compare it to a known working one.

I am going to a friends house tomorrow evening and trying my stuff on his machine. From what I have found, checking ohms across the two terminals on the ignition coil should read somewhere between 0.1 and 1.0 ohms.....I am getting a dead flat zero across both coils I have, so I could possibly have two bad coils. Who knows. Going to figure this damned thing out once and for all soon enough.....even if I have to buy everything brand new.

Thanks again Pud,

~Joe

i will keep my finger cross that it is just the cdi or coil.
do you have any pictures of your buggy. when i look up the mountaineer rtv 150 it shows that it is the same brand that sunl sell, newer model.
sunl.com or massimomotor.com which ever one they go by now.
they show parts for them but all out of stock.
i don't know how close my sunl 150b wiring is to yours but i have had mine opened up from electrical box to key switch.so if i can be any help there if the problem lies else where just let me know.
wiring diagram for these brand are impossible to find or the wright one or one you can read that makes any sinse.
also i never seen a wiring harness in there parts for this buggy.
from what i have seen the though my switch and other things look the same up at dash.


pud

Thanks Pud. I'll try and post a pic of the buggy this afternoon. Shoot, since it was so chep, I went ahead and bought another CDI box and ignition coil from the same people I got the stator from. Should be here Thursday, but I am still going to test out both my CDI boxes and coils on another buggy.

And you are correct, any wire diagram online or even the one that came with the buggy is completely different than the buggy itself. The book I have shows there to be about 3 or 4 more wires going into the CDI unit.....and i'm not mistaking them for the stator charging system. Plus, they are all sorts of weird colors thats not even there to boot. It's just about a worthless diagram.

Until this afternoon.....cross your fingers!!!

Thanks man,

~Joe

Ok, just got back for the test. Hooked both CDI units up to another machine and found neither one was working. Installed my ignition coils on his working CDI unit and found one bad one.

So, I just ordered another new CDI unit to replace this old and new one.

One question for you guys....the CDI boxes I have are rather large. The one that was on the buggy my buddy has is a pretty small one. The one I ordered is a little smaller than the broken ones I have......does the size matter at all?????

Thanks,

~Joe

One of the first questions I had for you is where the CDI is getting power. If it is getting power from the stator, it is AC powered and a little smaller. The DC powered one gets power through your ignition switch from the battery and is slightly larger. They are not interchangeable unless you rewire power...