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AR15.COM
8/13/2014 10:09:45 PM EDT
I picked up a small 110cc Chinese 4-wheeler for my son, and started having issues with it today.  When I first bought the ATV, it had been sitting for quite a while, so I had to clean the carb and replace the battery.  After that, it started and ran fine, with no issues.  Well, today it wouldn't crank.  I tried starter fluid, but no luck.  I pulled the plug, and it was a little fouled.  Cleaned it up, and still couldn't get the engine to fire even on starting fluid.  I tried spraying through the carb and directly into the head with the plug removed, no luck.  

I ended up checking fire at the plug. I was able to get spark, but not across the gap from the center electrode to the ground electrode.  It mostly wanted to fire to the side of the electrode, and never could get it to cross the gap.  I know at the very least I will need a new plug, but what would cause this?  I've never seen a plug not want to fire across the gap, so this is a new one on me.  I'll change the plug out tomorrow, but wanted to see if this is a common issue or see if there was a likely cause.
8/13/2014 10:22:54 PM EDT
[#1]
I can't speak for Chinese 4-wheelers, but crap-tastic spark plugs are pretty common on Chinese generators.

If you can find a NGK replacement, you'll probably thank yourself for getting it.
8/13/2014 10:30:38 PM EDT
[#2]
If I'm not mistaken, its a Japanese NGK plug that's giving me problems...
8/13/2014 11:12:15 PM EDT
[#3]
Replace the wire...
8/13/2014 11:15:59 PM EDT
[#4]
Whats the color of the spark.
8/14/2014 12:32:05 AM EDT
[#5]
Color appears to be bluish...
8/14/2014 2:28:53 AM EDT
[#6]
I bought a Honda Rancher a 2013 that had about 25 hrs on it. Guy bought it got ill two weeks later and died about a year after that never rode it again. About three hours into my stewardship (I installed hour meter)  it popped and died. It was the plug. Just change it and move on with your life. Have about 12 hours now no problems if you dont count the old lady leaving fuel switch on reserve so it could die on me once.
8/14/2014 2:33:11 AM EDT
[#7]
Electricity is pretty simple

It is taking the easiest path

Two possibilities- shit plug. Just cause it says ngk don't assume it is, it's from china. Or gap is really big
8/14/2014 2:36:33 AM EDT
[#8]
Check the wires first.
8/14/2014 6:32:28 AM EDT
[#9]
go ahead and order a cdi box, coil, wire, and intake manifold (if the carb is held up by the manifold exclusively).  Probably want to order a new carb to while you are at it.  I have a little 50cc craigslist special I bought for my daughter.  All of these items are prone to failing with regularity on the chinese quads.  The bright side is they are stupid cheap parts...I think the carb was 30 bucks.
8/14/2014 6:39:05 AM EDT
[#10]
Ive had something similar happen on my Yamaha GP1200 Jet Ski. Even though it has three cylinders it always missed on the center cylinder. I removed the plugs and it had the same symptoms you had. I replaced the plug and the coil and it was all fine. Im betting there is a crack in the plug or its a knock off.

EDIT: I would replace the boot too. In my case I also concluded it was also partially the coil. Every session the battery would be drained faster than it was chargining. The coil was bad and drawing too much. Now I dont lose charge
8/14/2014 6:39:22 AM EDT
[#11]
Sounds like you need a new plug, wire and coil. Alot of the time the coil will be strong enough to fire the spark plug nice and hot outside of the combustion chamber but once locked inside there is not enough juice left in the coil to properly fire it.
8/14/2014 6:41:29 AM EDT
[#12]
Ain't no gas in it.



Is the choke OK and operational?


ETA; saw he second part of OP
8/14/2014 6:46:28 AM EDT
[#13]
Check your grounds
8/14/2014 5:54:34 PM EDT
[#14]
Just cause it says ngk don't assume it is, it's from china
View Quote


Its a "Japan" marked NGK plug...

I didn't get a chance to pick up a replacement plug today, but I did check the plug wire coming from the coil/box (not sure of the correct nomenclature).  Apparently, it slipped over and has been resting on the exhaust.  Of course, its melted through the outer heat shield/jacket, but I couldn't see any evidence of it melting the inner wire.  That being said, its almost safe to assume it has, given my current issues with the ATV.  Unfortunately, you can't simply replace the plug wire, the entire assembly has to be replaced.  Given the 4 wheeler was running great before, seems like replacing the assembly will remedy my problems.
8/14/2014 6:31:30 PM EDT
[#15]
All of the parts can be ordered online for amazingly low prices.