Wont start/run

[djslyde]

Just bought a no name brand 70cc quad for my nephew to see if he would like riding. Its brand new. It ran fine for 10 min then it started to bogg out. I had it on choke for a lil while also but even when i had it on choke or not choke it would not idle it would just kill the engine if you didnt have the throttle pressed.it would start some times but now it doesnt even want to start. I'M Stumped..... Should have just payed the extra 1,000 to get a good one lol. wish i had that money any help would be great. wishing to give it to him tomorrow on his birthday (turning 2 :) ) but who knows now.. so please help me :D thanks alot

[Spike99]

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Couple of things to consider....


Electrical area:

Does it have spark across its plug?

Pull the plug and check for spark. If no spark, check kill switches, tether cords, etc.


GAS area:

- Does is have fresh gas?

Gas starts to lose its punch after 25 days from being pumped from the main gas pump.

- Does it have more then 1/4 tank of gas?

On same brands, they run out of gas when below 1/4 tank.

- Does it get good "gas flow" from the tank to the carb?

Pull the rubber hose from the carb and ensure it has good flow.

- Does it have an air lock in the gas tank?

Could have pinched air vent line or its vented cap could be plugged.


If it has spark (strong yellow to bright blue) and gas flow into the carb, it could have a stuck float needle (sometimes happens from rough shipping) or its carb could be dirty. It only takes one small spec of sand to screw up gas flow within the carb.


Give the above a try and let us know the results of each test.


thanks.

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[djslyde]

Thank you so much for posting that. Ill have to print this out and go out and check this. thanks again for all that i couldnt have asked for anything better. Ill let everyone know the results in a lil bit.

[djslyde]

Ok it does have spark but only when i held it to a metal object and not when its just hanging. It is fresh gas and its full tank. Gas flow was good it was draing good. i dont know what you ment by airlock in the tank.so how can i get to this float needle?
thanks again for this help

[djslyde]

OK I Think i have it. I think the vents in the gas cap are not letting any air in. i ran it for awhile it it off now and it start every time. I will see if this happens tomorrow i hope :D Is there any aftermarket caps i can buy? Or should i just drill a little bit bigger hols in the cap? I would do that but im just afraid that there might be some shavings stuck in the cap then get into the tank and clog everything up. thanks again for that check list

[Spike99]

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If you have good gas flow that is at a constant rate for 1+ minutes, then don't drill any holes in the gas cap. Good flow means air venting into the top of the tank, to let gas out of the bottom of the tank, is working great.

To prove the need for air replacement at the top of the gas tank... Take a normal milkshake straw and push it under a sink full of water. Put your thumb over the one end (the top tip) and vertically tip the staw out of the water yet allow 90% out its bottom remain in the sink's water. Notice that water still remains in the straw. Remove your finger from the top of the straw - which lets air into the top of the straw. Notice the water flowing out the bottom of the straw. Gas tank venting works the same way.

Yes, one must ground the side of the spark plug to something steel in order for it to spark across its gap. Sound like this is working great too.


Do you have a small engine or motocross / ATV shop in your area? If so, show them your gas cap. If possible, they will clean it vent holes and/or recommend a matching thread replacement - one that has working vents.

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[Spike99]

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I forgot to mention that some gas caps are sealed. To let gas into the top of the gas tank, there's a little 8" - 12" long "vent hose" that's connected to the top of the tank. This hose usually comes forward and goes down the steering column area. If this little hose is pinched or kinked, it will stop air from displacing the used gas within the tank. Before taking your cap to a shop (for cleaning &/or replacing), check for this "vented air hose" at the top of your gas tank. Could be a very simple fix.


Before letting your young rider take it for his/her first spin, please read the other "1st time" checklist items within:

http://www.atvfrontier.com/Forums/viewtopic/t=14756.html

Note: Its a long check list but to me, each item is mandatory - until you get very comfortable with your new mini.


Hope this helps as well....

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