Whatever you unplugged wasn't the ECU, there is no way it could run with that missing.

 

theres a CDI, couple solenoids, voltage regulator. I promise I unplugged it and it started. Ill go do it again just to verify.

This is what I unplugged.


http://www.ebay.com/itm/2002-KAWASAKI-PRAIRIE-650-ECU-X4255-/261603712864?hash=item3ce8cbdf60&vxp=mtr

 

I am not familiar with the 650. Kawasakis are rare in the UK, except for the KLF 300 and 400. It seems to have two ignition control units the "Igniter" and the ECU so I guess this ECU doesn't do what a normal ECU does, my mistake.

 

Heres what its doing, im attempting to rev it in the video, spitting gas back.

 

Finally found something broke. Sheared flywheel key. Im sure this had the timing extremely retarded. Now the hard part, waiting for parts.

 

I recieved a personal message on this because I never updated the outcome on this thing.

Turns out previous owner damaged the flywheel when rebuilding it before I bought it. He ordered a used replacement from ebay. That turned out to be the wrong one with magnets in the wrong place causing the timing to be way out of whack.

Only reason I found out was when u was looking at the parts page, I noticed the magnets were not the same. So I pulled it and ordered one for my exact model, it has ran like a dream since.

 

I wonder it is the rubber boot from the carb to the engine.

 

I bought a ‘01 prairie 300 a couple years back for 1k( about 1,500$ less than similar atvs were selling for), the owner couldn’t get it running right and gave me an extra carb that he’d ordered thinking that was the issue, I think he said he’d tried a couple cheap eBay ones as well and still having issues Well I was giving it a once over in my garage before tearing it down and saw that the hose clamp holding the rubber boot on the air cleaner box had came off and wasn’t seated properly. 10 seconds later and the thing ran like a champ!! K.I.S.S.
This atv has been great for cruising around camp with the kids and hauling **** around the little mine site I have. But just lately it will die out of the blue and then fire back up. Although the last time was more of a half hour wait situation. I know these are air cooled so my question is, what can I do to keep it from overheating? I think that’s the issue as it was the highest temps of the summer… although I have zero idea how this cooling system works so if anybody can give me a dummies idea I would appreciate it.

 

An overheating engine will usually run until it seizes, so I would guess this isn't your problem. Stators are the usual suspects as they get hot along with the engine and can fail when hot, but run once cooled slightly. However all the electronics can do that, just takes longer for them to heat up. Worth checking if the regulator is overcharging, as that can cause other electronic parts to overheat. The first thing is to change the plug. If you can, check if it is sparking with the fault on, this narrows it down to if it is an electrical problem or not. A blocked tank vent, or low float level, can cause problems too.