'03 LT400Z running perfect when parked, now won't run unless choked
 

Hello all,

I have an 03 Suzuki LT400Z quad that was running PERFECT last time I rode it last summer. I let her sit all winter and now when I start her, she runs great
in choke (idles and revs) but dies immediately when turning the choke off.

I have...

1) taken the carb apart (it looked very, very clean inside) and cleaned everything just to be sure.
2) put it back together and it still does the same thing.

3) I then took the carb apart again and REALLY went through every part, making sure everything was clean and in excellent condition.
4) I also took the petcock valve off and cleaned the screen (it too was very clean) and made sure fuel flow was good.
5) put everything back together and it still does the same thing.

6) installed a new NGK CR7E plug and still does the same thing
7) reseated the carb seals and tightened very tight to make sure no air was leaking...

Still, won't run off choke...

It's seems odd that it ran PERFECT before sitting, and now mysteriously won't run unless choked.

What should I do next? I want to sell it but need to get it running perfect first...

'03 LT400Z running perfect when parked, now won't run unless choked
 

You cleaned the pilot jet??

'03 LT400Z running perfect when parked, now won't run unless choked
 

I cleaned every part, including all the jets I assume. Everything looked perfectly clean. All the little holes in the jets were perfectly clean.

'03 LT400Z running perfect when parked, now won't run unless choked
 

Some of the other things I have done is...

> cleaned the air filter
> sprayed wd40 around the carb/head/airbox connections to see if idle changed and it did not.

'03 LT400Z running perfect when parked, now won't run unless choked
 

<div class="FTQUOTE"><begin quote>Originally posted by: CurtisR

I cleaned every part, including all the jets I assume. Everything looked perfectly clean. All the little holes in the jets were perfectly clean.</end quote></div>

The center hole was clear? Did you hold it up to the light, to see if you sould see completely thru the center hole ( like looking thru a telescope)? The symptoms you describe fit a plugged pilot jet perfectly.

'03 LT400Z running perfect when parked, now won't run unless choked
 

I assume you're using fresh fuel, what happens when you turn up the idle screw? (If the jet's not plugged)

'03 LT400Z running perfect when parked, now won't run unless choked
 

Hi,

I poked a wire through all the little holes in the jets and they were clear. I turned
the large black idle knob and there is no change to whether it dies or not when turning the choke off. (of course the idle goes up or down when I rotate the knob so that is working)

'03 LT400Z running perfect when parked, now won't run unless choked
 

Yes sir, I drained the tank and refilled with hi-octane fuel as well. Sorry, forgot to mention that... Ugh, this little problem is driving me crazy! [img]i/expressions/face-icon-small-smile.gif[/img]

'03 LT400Z running perfect when parked, now won't run unless choked
 

Is there an idle screw on the carb as well as the large idle knob? All the idle knob does is adjust the throttle cable mechanism to raise the idle that way. Is there a screw that adjust the air/fuel mixture as well?

'03 LT400Z running perfect when parked, now won't run unless choked
 

<div class="FTQUOTE"><begin quote>Originally posted by: CurtisR

Is there an idle screw on the carb as well as the large idle knob? All the idle knob does is adjust the throttle cable mechanism to raise the idle that way. Is there a screw that adjust the air/fuel mixture as well?</end quote></div>

Yep, bottom side of carb, just forward of the float bowl