purchased a 70cc maxam atv. turns over, has spark, gas in carb bowl,

former owner parked it in fall 2010, was running well. trying to get this thing going but just doesnt seem to want to start. took carb apart looks clean float seems to be ok needle looks ok. put gas directly in plug, no go
heated plug up, no go would appreciate any help have a very disapointed little guy right now

 

gas in carb, you have spark,,,,ok.
when you crank it, have you checked to make sure the spark plug is wet with gasoline to verify that the carb's jets are sending fuel to the cylinder? just because the gasoline is in the float bowl doesn't mean the jets are sending it to the cylinder. that's why i'm leaning towards a fuel delivery issue. one way to verify a fuel delivery issue is to conservatively spray a shot of ether/starting fluid into the intake/air filter. if it fires up and runs, you have a fuel delivery issue. if it doesn't, we gotta look further.
now, with that said, have you done a compression check. i'm presuming this is a 4 stroke?

here's my prediction for this quad: we'll get it running after you remove the jets and clean them. that's probably what'll end up happening. but these tests will lead us in that direction.

 

Thank you for replying jaster94. yes it is a four stroke, after i posted i returned and tinkered a little more and found that the plug seems dry so i think you are right carb issues. about starter fluid never done that before, but if you spray fluid threw the carb air intake and the jets are pluged how can it start I am not doubting u just a question, will go and buy some starter fluid today and a can of carb cleaner (pretty sure I am going to need it). something else i noticed is a unit connected to the gas line that has a hose connected to the manifold between the carb and the engine it is the size of a quarter says ( in , out , vent ,) is this vent using the prime of the engine to draw gas to the carb? never seen that before. if it is should i bypass it to make sure even though the float is full or am i just putting the cart in front of the mule. thanks again. c.b.rookie

 

when spraying the starter fluid into the intake/air filter, it is not going in to the jets/float bowl. pretend it is RICH "air" that'll burn. (like propane vapors). you're spraying on the air side of the carb.
now on that quarter thing, are you talking a petcock valve, fuel filter, or what? if fuel hoses are connected to it and it is plastic, i would think it is a B&S fuel filter. you probably need to take a picture or two of what you got.

 

took apart carb cleaned it all out looks prestine. jet holes are clean springs look ok, reassemble turn over and nothing.. when i turn it over she just cranks when i pump the throttle it sounds like it speeds up a bit almost like it wants to go.. even sprayed some starter fluid into the air intake of the carb nothing, double checked plug is wet, cant see spark but when i turn it over and i touch the end of the plug (like my son says dad you should see your eyes they jump!!) so there is defenitely spark. now i am really confused everything seems to be there but she just doesnt want to fire up?????

i beleive it is an electronic choke, the electric starter switch goes left and right but there are no emblems or stickers so i am not sure about it. could it be the choke malfunctioning and it is not getting enough gas?

 

that switch should be in the middle if it is a left/middle/right switch on your left hand.
so, the spark plug is wet with gasoline, that's a good thing. now, did you ground the plug to the jug/cylinder/head while it's connected to the coil wire and you're cranking the engine? we need to see if that plug has good spark, mediocre spark, or if it is malfunctioning and grounding out. is it the factory plug? if so, upgrade to the NGK brand. forgive me, i know not what particular size. o'reilly's ought to be able to find the equivalent size. if it didn't fire up on starting fluid/ether, then i'm thinking the plug is fouled out and grounding out.

 

thanks jaster (dam your good, pardon my french) double checked the fire, started by spoiling the engine to a new plug, fire looked great tried it samething, then triple checked and there was no fire checked things and found that the coil has a split right at the coil itself looks like water got in froze and split the coil. so after many attempts the fire is intermitent, guess that means going shopping for a coil. on-line like 20 bucks, gonna see if i can get local. also noticed the electric choke is really hot (part at carb) i dont feel it moving when i start the bike. this is a keihin cvk carb can i swap that out for a manual choke? (simpler is better in my book).

thanks again jaster, with that being found my little guy has a better outlook now he was getting pretty down when his old man couldnt figure it out. not saying i am done yet but i am surely one step closer.

 

From your description it does suggest that your coil is bad. There may be other problems too, but that is definately the place to start.

On your choke - it should get hot, and you won't feel it move. This is not a solenoid. The choke (actually more correctly called a bystarter valve) has a heater in it. This heater gets hot and expands a wax pellet that pushes closed a valve that opens an extra fuel passageway when cold. This valve "closing" happens very slowly over several minutes.

Note how this is vastly different from the standard "choke" that starves the fuel/air mixture of air to increase the fuel/air ratio when cold. The bystarter valve adds an extra fuel passageway to the same amount of air to increase the fuel air ratio when cold. Its the same general idea (the engine needs higher fuel/air ratio when cold), but implemented in a completely different way.

 

WOW! i learned 2 things on this post. how the bystarter valve works AND the fact that i did not know that a coil could split and STILL have intermittent spark. i gotta remember that.

Note to Self: remember this post

 

in my humble opinion, ALL Dads have to be the hero to their kids. if they ain't or don't attempt to be their hero, then they ain't worth being a Dad. they're just a biological father then. kind of hard liner on that train of thought, huh? that's just my two cents. sorry if it was a nickel's worth. i mean kids nowadays need a mentor, an example, an inspiration, someone to look up to, to aspire to be like or similiar to, a Dad. that's who fills that gap.