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Discussion Starter · #1 ·
Hi forum,

I have this 200cc Chinese ATV, that won't start.
I have thoroughly cleaned the carb - new oil - new sparkplug - new battery - new gas. When trying to start it sometimes makes a little sound/growl from the engine.

Any ideas here? Also, does anybody know what is under the hex bolt red circled?

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That will be a valve adjuster under the circled cap. There will be another cap for another valve.

The way to test for no start is to try starting it for a few cranks, then take the spark plug out and see if it's got fuel on it. If it's dry, then either it's not getting fuel, or it is getting fuel but it's being burnt, which means it's trying to start. It the spark plug's wet, then you need to attach the plug to it's lead, rest the plug on a metal part and watch for spark as you crank. If it has spark, then we follow one course, if no spark, we do something else.. Basically though, you keep putting the plug in and out checking for fuel and spark after every few attempts to start it.

Check for fuel and spark and let us know and someone will suggest what to do next.
 

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Discussion Starter · #3 ·
Hi Mech,

so both the old and the new sparkplug make almost no spark. Sometimes it does a little, but the majority of the time it makes no spark when turning.
It's dry as well - maybe a little black soot on them.
 

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The black soot means there is a spark and fuel some(and probably most) of the time. An intermittent spark will cause that soot though.
The spark should look blue. If it's yellow it's a bad sign. A skinny blue spark is ok, It needs to be regular though...If you can get the sparkplug lead's cap off, take that off and check the spark by holding the end of the lead close to the engine. There should be a blue spark every second rotation of the crank at a good cranking speed. The spark might be skinny, and it might not jump more than about 3mm, so you need to be watching closely, and in the shade or dark is best. If the cap doesn't come off then recheck the spark in a darker place and check it's regular, every second rotation of the crank.. If you have a test light, you could look at that to check the spark is regular.
The other reason for black sooty plug is that it's getting a bit too much fuel, not so much that it floods, but enough to make it run rich. That though requires it to be running. You said you cleaned the carby.. did you strip it down and clean the jets etc ? Are you sure that is all in good order ?

The other reason for soot is that it's trying to start, (and firing to make the soot), but it just needs the right combination of choke and throttle to coax it into life.. which is common after a carby rebuild .. If the choke is a plunger type, then it only works when the throttle is closed. If you wind the idle speed up, or open the throttle trying to get it to start, the choke will stop working.Sometimes winding the idle speed screw back a lot, and leaving the throttle alone till it starts firing and speeding up a little by itself as you operate the starter, and then just the tiniest bit of throttle till it clears and starts to run clean, is all it takes. Wind the speed back, try it with choke, then without the choke, or perhaps checking if the plug is wet in between tries.. If the spark is regular, it probably will coax into life.
 
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