I'm just a casual rider and in the winter, my ATV is used for plowing snow. I'm the original owner and the winch for plow lifting is a Warn. Pretty sure the brushes are wearing on the winch as it makes a bit of a screech when used. I suspect this draws down my battery as I can hear the solenoid chatter when I first turn it over to start, but this goes away after it warms up, so I think it's charging. The battery is old, but takes a charge which will turn the engine over quickly without the solenoid noise.

After a big snow storm and hard work, it failed to start the next morning. I had just filled the gas tank. I opened the train screw on the carburetor and it's getting gas. I replaced the spark plug and after cranking over quite a bit, it failed to fire. I grounded the plug and saw no spark when I turned it over. I even held onto the plug to see if I could get a shock and couldn't.

Where do I start troubleshooting this problem? Is there a schematic that shows the parts used in ignition process from battery to plug? Always started easy. Are their points involved? Thanks for any help.

 

The ignition system on most "big name" quads is quite complex. The earlier Big Bear was, I haven't done an 03 but I guess they will be even more so. Best advice is to buy a workshop manual and go through the fault tracing listed in it. Charge the battery too, solenoid buzzing is a sign of a low battery or loose connections.

 

Thanks for the suggestion. I figure a manual is due and the battery won't go another winter either.