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Discussion Starter #1
Hi everyone, having an issue with my quad and looking for some suggestions, etc....

I have a 2003 ltz400 that I let sit over about the past year or so with gas in the carb, etc., so it wouldn't start ( was running fine when put away last ).

So I took it somewhere to have the carb cleaned and gone through, etc. They supposedly did a compression and leakdown test and said it had low PSI and maybe an exhaust valve leak possibly.

This sounded fishy to me since it was running fine previously so I had them stop working on it and got it back to finish the carb myself. So basically I replaced the choke parts/cable and the entire needle valve assembly as it looked a bit worn and I lost the little spring on the old one.

Get it all back together and it still won't start. Seems to have a spark, can't tell how good of a spark but it looks like any normal decent spark I've seen before. When I manually choke the carb by putting my hand over the back my hand gets wet with gas. When I pulled the plug it had a bit of moisture on it.

Could it actually have low PSI and that is what is causing it not to start? They said it tested at around 40 PSI when it should be 120PSI but I don't trust the people I took it to. I thought even if it had low PSI it should start but maybe not run good?

Any thoughts, suggestions, ideas or anything that may help would be greatly appreciated, thank you in advance.

Mike Rogers
 

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Since it has set for over a year I would put a new plug in it and make sure the battery is fully charged before you try to crank it or have a booster battery charger hooked up to it. I would think even with low PSI it should still crank although it probably wouldn't have the greatest power to it. Also while you have the plug out spin the engine over a few times to make sure there isn't any extra fuel just sitting in the combustion chamber. Might not work but worth a try. I hope this helps you some.



THOMAS
 

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I should have said this above but I have a new battery in it and what appeared to be a brand new spark plug as well although I don't have a gapper toold handy to make sure it's correct but the gap looks like it should be fairly close...

But the quad is cranking, there's no problems there, it cranks over just fine. I've got it to backfire a couple times and it sounds like it almost wants to start but not quite.



Since it has set for over a year I would put a new plug in it and make sure the battery is fully charged before you try to crank it or have a booster battery charger hooked up to it. I would think even with low PSI it should still crank although it probably wouldn't have the greatest power to it. Also while you have the plug out spin the engine over a few times to make sure there isn't any extra fuel just sitting in the combustion chamber. Might not work but worth a try. I hope this helps you some.
THOMAS
 

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I am not sure of the name of it but there is a thing that is supposed to slide up and down inside the rear of the carb that has a pin that controls the float level when you are spinning it over look at the rear inlet of the carb and make sure it is trying to move up and down and not stuck, Mine and my brother in laws bike had the same problem. I had to take the lid off the top of the carb and spray the inside of the carb with some WD-40 to allow it to slide freely after that and making sure the float was set correctly we haven't had anymore problems with the carb.



THOMAS
 

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Yes that is the Piston Valve & Jet Needle. It moves freely by hand but when I am trying to start it, it does not try to move on it's own.

This brings me to another thing when I got the carb back it was missing a tube, on the schematics for this carb it's #49 just called a "Hose" that connects to the top of where the piston valve & jet needle assembly are.

I was told this was just a vent tube and that it shouldn't make a difference, can you check on yours to see where this tube goes and if it is just a vent tube?

I had a suspision that is was supposed to be vacuum but could not find anywhere that it would possibly go...


Thanks for your help/input so far!



I am not sure of the name of it but there is a thing that is supposed to slide up and down inside the rear of the carb that has a pin that controls the float level when you are spinning it over look at the rear inlet of the carb and make sure it is trying to move up and down and not stuck, Mine and my brother in laws bike had the same problem. I had to take the lid off the top of the carb and spray the inside of the carb with some WD-40 to allow it to slide freely after that and making sure the float was set correctly we haven't had anymore problems with the carb.
THOMAS
 

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That does look like a vent tube only and shouldn't be making it not start. I would definitely take the cap off the top and spray it with some lube, also you may want to stick your finger in there and while your spinning it over move the piston valve by hand and see if it tries to start easier if it does than definitely spray it put it back together and see if it makes a difference. No problem I know mine gave me a bunch of probs getting it to crank after fresh build and don't want anyone else to have the same problems.



THOMAS
 

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Ok upon further review that is bouncing up and down when I am turning the quad over trying to start it. It's not traveling real far but it is going up and down on it's own.

I went ahead and took the top off anyway and sprayed it all down with wd real good just for good measure...

I have also tried to move it by hand at slow intervals while cranking it as well with no luck.

I'm starting to think even though that is a vent tube it may actually have some significance... I may just order it and see what it does but for a hose it's like $19 which makes me think it actually serves some kind of purpose because just a piece of hose should only run a couple bucks...
 

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Hmmm sorry man I'm stuck on what else to tell you to try. Maybe someone else will have some ideas.



THOMAS
 

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I wish I could offer some advice. It tough to work out a carb problem and not be there to look at it.

May want to take it all apart again and using a good schematic and make sure all the pieces are there. Make sure the jets really are clean if you didn't replace them. I've had them look clean before, could see through them and everything, and it still had a piece of grit in it blocking fuel flow.

Take your time putting it all back together.

Have you checked to make sure you are getting a good spark?
 

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Ok yea I finally got it started and it idles good but rough when giving it a good amount of gas so I am thinking even though one or more of the jets/needles seemed clean when I put them back maybe they weren't completely like you said maybe something tiny in there somewhere...

But I made a lot of progress!

So my next step is to just go get the rest of the jets and just replace them...

I'll let you know.


I wish I could offer some advice. It tough to work out a carb problem and not be there to look at it.

May want to take it all apart again and using a good schematic and make sure all the pieces are there. Make sure the jets really are clean if you didn't replace them. I've had them look clean before, could see through them and everything, and it still had a piece of grit in it blocking fuel flow.

Take your time putting it all back together.

Have you checked to make sure you are getting a good spark?
 

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Cool, You may want to take it back apart like Bojib said and get you some brake cleaner and spray the crap out of it everywhere to make sure everything is clean or replace everything, but make sure you spray it good with WD again to make sure everything moves good when you start driving it again. I'm glad you got it going even if it's not as good as you want it yet.



THOMAS
 

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Ok I have taken the carb completely apart again and recleaned everything with carb cleaner and compressed air. Still having the same issue...

I do have one thing that I'm not sure of, there are two screws on the side of the carb and two pieces where the screws go into. I do not know what the orientation of these should be and they are not in any parts diagram anywhere. Here is a picture of them, I have circled them in red.



Can anyone tell me on what side these pieces go and in what direction???

They look like they have something to do with stopping the float from raising too far but they really don't seem to?

I have tried them a couple different ways with no luck and I'm not even sure if they are an issue at all but since I had no clue which way they go ( since they were just off completely when I got the carb back ) it would be nice to at least know how they are supposed to go so If that doesn't fix my problem I can at least mark it off my list....
 

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There should be two tabs on the middle of the float, one that goes up against the needle and the other that goes against the rear of the housing where the needle goes into that controls the float level both rise and drop of the floats. As far as what orientation those tabs are supposed to be in I'm not sure, but it looks like it could be to control the fuel going into the overflow tubes on top of the carb, but I may be wrong on that.



THOMAS
 

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i have the same exact problem wit my 2004 DVX 400 arctic cat it will not start . it idles fine but when i gave it gas it would bog out and die. so i took the carb off and cleaned it and put it back on and now it wont start at all. it will backfire and try to start but it is acting like it not getting enough gas to start. and i can't figure it out. did you find out anything on yours
 
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