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Discussion Starter #1
It starts and idles fine. Took it apart, gave it bath in an ultrasonic tank for 30 minutes. Didn't do a whole lot that I could tell. Shot the carb body with some carb cleaner, bathed it in Simple Green mix, then took my compressor and shot some air through the passage ways. Put new jets in and checked the diaphragm (which looks like new). Reassembled it, fired it up, let it warm up and then set the idle speed and the air mixture. It ran fine for a couple of days, made some nice donuts in the back yard. Let it sit on Sunday. Fired it up on Monday afternoon and this is what I get (see Youtube video). Air box isn't connected right now and it has a new air filter in the air box.


Any ideas?
 

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First off connect ALL pieces of the air intake system......these quads are picky about that.......If you have a vacuum operated petcock,( PRI -ON -RES) check the vacuum line for fuel in it....if there is, that is at least part of the problem.
 

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Discussion Starter #3
It runs the same with the air box connected. It has a new air filter. No fuel in the vacuum line to the petcock.
 

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Check for fuel in the fuel pump vacuum line
 

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Discussion Starter #5
No fuel in that vacuum line either. Just switched out (temporarily) the vacuum fuel pump for an electrical fuel pump (8 psi max), same problem.
 

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Just for kicks....check the carb vent hose to see if it is not stopped up
 

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Discussion Starter #8
Okay, did a basic tear down. Checked jets and they're clear. Put it all back together and hooked up the air box (btw, what a pain to connect the hose from air box to carb). Runs like it should, just the idle is a bit high. So I'll wait for it to cool down (good time to make burgers for dinner, even though it's raining outside). After dinner I'll see if it repeats its problem.
 

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Discussion Starter #9
Well that didn't last long. Ran fine, but idle was high. Made the burgers and had dinner. Went back out, fired up fine, went to go run down the road and it started sputtering again.
 

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Check your voltage at the battery while idling and reved up a bit.....it should not go over 14.7v at any rpm
 

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Discussion Starter #12
It's the factory setting as far as I know. I didn't tweak it any. I'll check it tomorrow. I'm wondering if I'm picking up crud out of the tank still. I left it on the atv, but pressure washed it inside twice. Couldn't see any gunk inside the tank. But when I tear the carb apart and reassemble, it runs great until it shuts down and sits. Then it's back to struggling. I'm beginning to think there's small crud still in the tank getting sucked into the carb.
 

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I went thru this with my KQ300...It sat for a number of years before I bought it. Rebuilt the carb 3-4 times...replaced voltage regulator....I would be riding and go to hit the throttle... and it would bog similar to yours. If I slowly hit the throttle it would seem to be ok (most of the time). Last season I got a can of carb cleaner that I could soak the carb in all night. It did it a couple times after that. But I got to riding it and it seem to clear up. I even bought a diffuser tube ( expensive lil part) that the needle slides up & down thru. BUT after sitting out all winter for hunting season & having Seafoam in the tank, I havent had it bog down this year!! I didnt have to tear the carb out again to install the diffuser tube.
I added a fuel filter between the carb & fuel pump. In all my honesty..I couldnt tell you what it was from on my quad ..But I think you're in the right area with the fuel tank crud.
IF you do decide to soak the carb...be sure you remove the plastic slide yoke. It has 2 security torx bit screws holding it in.
 

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Discussion Starter #14
Tigmonster, I picked up a filter last night and a can of Seafoam. Planning on pulling the carb again just to make sure none of the jets didn't get junk in them and check the float height, then put the filter in place after the fuel pump.

TCIII, voltage at the battery is okay.
 

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When mine did that, it was because the diaphragm was slightly pinched and the slide wasn't sliding easily up and down. Took me 3 tries to get that diaphragm in there perfectly. The trick is to not twist the cap at all. Even a 1/8" twist will be to much. Gently set the cap on lined up with the screw holds and push straight down.


The other issue I had was my float was set at 13.5mm (book said 12-13mm). When it was like this, it would get up to about 3/4 throttle and start sputtering, starving for fuel. Dropped the float down to 12.5mm and that problem went away.

Also, one more thing. As the spring for the diaphragm gets older, it can either get easier to compress or stiffer. I replaced mine and that made a difference on the smoothness of the throttle up.
 

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Discussion Starter #16
Okay, finally got back to it. Took the carb off to check the float. Float is at a 1/2 inch (12.7 mm), so that's good. Checked all the jets again and they're clear. Checked the passage ways, ditto. Added a filter after the fuel pump. Put it all back together. After the it primed up and started, run good for about a couple of minutes. Then it started to bog down at the slightest touch of the accelerator. It idles nicely though and starts without problem.
 

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Discussion Starter #17
Out of curiosity, can anyone tell me what the flow rate/psi for the fuel pump should be? I can't find any specs on that.
 

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start it up, let it warm up for 5-10 minutes, then grab the throttle and hold until it dies (providing it actually bogs out enough to die).


Then pull the spark plug out and let us know if it is wet or dry.


Also, is the choke closing all the way? What happens if you put your hand over the air intake and apply throttle?
 

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Discussion Starter #19
It still bogs down after warming up, but doesn't die, just gets close that you think it's going to stall. Pulled the plug and it was dry, but it's black as night now. That was a brand new plug.

The air/fuel mixture screw is about 3 1/2 turns from bottoming out. Can't find any spec for how many turns it should be. I've been told a good place to start is 2 1/2 turns and adjust as needed. It was popping at 2 1/2 so I turned it out to add more fuel, so I might need to turn it back a 1/2 turn since the plug is black now.

I'll check the choke this afternoon.
 

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I think specs on the screw are around 2 1/2-2 3/4
Have you tried moving the clip on the metering rod up and down.....also did you put the spacers on it back in the correct position
 
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