Quad back fires and dies

[miami1]

the air screw is a brass philips head screw on the bottom of the carb, next to the float bowl. The screw faces down when the carb is mounted

and is visible when the bowl is on!

 

[elwood]

yes it's visalbe, and an edit I said it was a philips head but it is a flat head

 

[deerman2701]

That might be my problem I took out a screw it looked like a screw and I just put it all the way back in. I though it was a pilot jet. Haha. Where are the pilot and main jets located?

 

[elwood]

the jets are in the bowl air screw, idle screw and drain srew for the float bowl are outside the carb

 

[deerman2701]

Man I must be reading some false stuff haha. I thought the air screw was a long needle that goes through the carb haha what's that needle called? It's like 4 or 5 inches long

 

[elwood]

it's called the needle

 

[deerman2701]

What's the needle do?

 

[elwood]

http://www.yfm350.com/forums/showthread.php?t=15050

 

[miami1]

once you find your air screw turn it all the way in (lightly) then turn it out 2.5 turns, this should get you close enough to fine tune it. if you read the thread in the link above it should help you understand which jets are being used at certain stages of throttle. the air screw for instance conrols the idle fuel/air mix and leads into the pilot then the needle then main jet.

and the hip bone is connected to the leg bone

 

[deerman2701]

UPDATE


Got my quad to idle pretty good while fiddling with that screw


BUT (Theres always a but eh?)


When its at idle and i floor it all the way to it bogs and dies, i cant remember if it used to do this, but if i lightly throttle and then goose it it is fine....is this normal?

Also when i goose it a little bit of smoke comes out is that called being rich? it also pops a little bit.. what can i do to fix this or should i just run it

 

[deerman2701]

UPDATE

It seems like the overflow line drips some drops of gas.. is this normal?

Also i dunno if its always been there or just ripped but the intake boot has a small tear in it would this cause all of my problems? the backfiring and dieing and not starting for about 5 min

it seems like when it backfired and stalled the quad got flooded im not sure though

 

[elwood]

You NEED to fix or replace that intake boot before you will get it to run right, fix it first then check to see if there is any other problems that need addressed.

 

[DirtBikeDad]

UPDATE


Got my quad to idle pretty good while fiddling with that screw


BUT (Theres always a but eh?)


When its at idle and i floor it all the way to it bogs and dies, i cant remember if it used to do this, but if i lightly throttle and then goose it it is fine....is this normal?

Also when i goose it a little bit of smoke comes out is that called being rich? it also pops a little bit.. what can i do to fix this or should i just run it

Was having very similar symptoms with mine and turned out that the accelerator pump was frozen up. (Find the shaft that runs from the float bowl up under the plastic cover where the throttle cable attaches. Hint....it is supposed to move, mine didn't):haha:

 

[deerman2701]

UPDATE

I did the spring pen thing and now the plunger moves better, and got a new intake boot but the problem still prevails.


I get it to idle fine but once i gun it the quad just dies and it doesnt start for about 5 min later after sitting...

Like its getting flooded or not getting enough fuel....

It has good compression and spark what else could be wrong with the carb or anything to check?

 

[deerman2701]

UPDATE AGAIN

I swapped my buddies carb and my quad ran fine so that leads me to believe something in the carb of mine is messed up. Any suggestions what this would be? i changed the spring so the plunger is a lot better now but i dont know much about carbs to rebuild or diagnose.

I swapped in new jets - no luck
I used a clicky pen - no luck
I cleaned the whole carb - no luck

Anything else?

 

[DeadLastRacing]

you float have hole in it? Is it set right?

 

[deerman2701]

No hole in the float, and i dunno if it is set right, i have really no knowledge of carbs. is there a way to check? someone told me it might be a stuck needle? I have a guy gonna rebuild it tomorrow you think this will fix it?

 

[juggaloclownz187]

Take the float off and see if it floats in a cup of water..... Check to make sure theres no dirt (or flies lol) under the needle that is attached to the float, and that the float is set at the right level.....

Also take your air box lid off and see if it is flooding gas back into the air box, or if your filter smells like gas or anything out of the ordinary....

 

[DeadLastRacing]

Use gas, Water and gas have a different dentesy. And if there is a very small crack of hole in it, the gas will flow into a smaller opening then the water. Level for the float is in the manual.

 

[Spooner]

Take the float off and see if it floats in a cup of water..... Check to make sure theres no dirt (or flies lol) under the needle that is attached to the float, and that the float is set at the right level.....

Also take your air box lid off and see if it is flooding gas back into the air box, or if your filter smells like gas or anything out of the ordinary....

wait your air filter isn't supposed to smell like gas? oh ****. lol how do i fix this?