I bought a 110cc Coolsport Atv for my grandaughter.I don't know much about Atvs in general but I had never heard of the Coolsport.She saw and wanted it and the rest is history!!The problem we are having is, after she had riden it for about 5-6 days it would not start.My son pulled the sparkplug out and it was very black and looked burnt.He put a new plug in and it cranked and run fine for about 4-5 days and the same thing happened again.

 

Maybe a fuel problem. Are you using the high octane that is recommended for these ATV's.

 

Here is a link showing what the spark plug should look like, and how to interpret the cause when it isn't right:

Reading your spark plug link

Black sooty plugs mean you're running rich. It could be that the plug is so fouled that it won't start, but mayber there is another cause. When it won't start do the basics: Are you getting fuel (plug wet with gas after cranking)? Does the engine have compression (use a compression checker)? Are you getting spark (use your old cleaned up spark plug outside the engine with the threaded end grounded to the engine case)?

 

Don't think they are using high octane,just reg. gas.
I'll let them know about the fuel.Thanks so much,hope this will work.
Thanks again...Jack Uzzell

 

What do you mean by "running rich"

 

Running rich means the air/fuel ratio has too much gas and/or not enough air. Beacuse of that there is a lot of gas that doesn't burn (the combustion process runs out of oxygen before all the fuel gets consumed).

 

It may be a simple carb adjustment needed.... The fuel air mixture mays be adjust to rich... as in dumping too much fuel into combustion chamber.. this will make the bike run rich and not be able to keep up with burning all the fuel. There are two adjustments on these carbs... Idle adjust is the screw with the spring and air/fuel is the slotted one with no spring. Get the bike started and warmed up with new plug for minimum five min. Now adjust the IDle screw with spring left / right Till the bike idles properly without shuting off. then raise the rear end of the bike and have someone throttle bike up and adjust mixture screw left/ Right till you find the sweet spot that lets the engine rev to highest RPM. Now recheck idle to make sure it is settles in well just sitting there.

 

Thanks alot!!