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Discussion Starter · #21 ·
This King is a 99 and it is still killing me! Since replacing the rectifier, the quad will run beautifully. But, it will not idle for more than 15-30 seconds. I have been adjusting the pilot jet. Factory setting is 2 5/8 turns out. I ran it all the way into 2 1/8. The spark plug is a chocolate color after running for 5 minutes when you shut it off HOT. If I let it idle, it will die after 15-30 seconds and then the only way to get it to restart is to peg the throttle and beat the snot out of the starter for 10+ seconds. When I have checked the plug before it would start, it is gas fouled. So, I kept leaning the mixture to 2 1/8. So, first question is, is that too much adjusting from the 2 5/8 stock setting?
I restored it back to 2 5/8 and I am going to have my son run it like that for 10 minutes and bring it in hot and shut it off immediately. We will then assess the plug color to see how it looks. If it does not look rich, I will then pop it back in and let it idle. When it dies, we will pull the plug and see if it is gas soaked or what. If it is, I am going to put a brand new plug in and see if it starts right up.
Any thoughts? My guess is main jet is fine because the quad is responsive at 3/4 and up throttle. Needle jet should be fine too since mid throttle is fine. The pilot jet is my concern, I think. Also, the diaphragm in the carb seemed fine and I think if that had an issue, I would have bigger issues with running. The Petcock was replaced and is OEM. I have not touched the fuel pump.
Any comments, thoughts or suggestions? Thanks.
 

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Discussion Starter · #22 ·
We played with this again yesterday and the quad stalled. We then checked the plug and it was bone dry. What is the issue with the petcock on these things? PRI does NOT flow gas freely like it does on a Ozark without a pump. The fuel pump makes things a little more confusing on these. In addition, the needle jet is set in the fourth position. Anybody know where it should be? My son says he saw a video of a 1996 with it in the 2nd position. On a good note, battery voltage is fine. But, I have cleaned this carb and we have it back out again. We can't get this thing dialed in. I also noticed you cannot by an OEM carb diaphragm. You have to buy the whole assembly for $200. Something is unhappy and needs to be sorted.
 

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IIRC you’ve replaced the petcock, so we’d like to think that’s not the problem. I think my QR had an issue with idling when the petcock went out many years ago under warranty. Sounds like the issues you have are much more extensive than that.

My QR has had running issues in the past when the fuel pump stopped working. Are you pretty sure the fuel pump is functioning correctly?

You could try bypassing it and using gravity feed fuel to isolate the petcock and fuel pump from the system.

I’m no help when comes to the guts of the carb.
 

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My ‘00 KQ 300 when set to “Pri” works as it should. Fuel will continuously flow out instead of pulsate like when set in the On position. I know this as I’ve tried it once. Not sure why it’s not flowing out for you when set to “Pri”. Seems rather strange.
 

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Discussion Starter · #26 ·
If I pull the fuel hose off of the carb and switch the petcock to PRI, it does not flow constant. It still goes through the pump first, which I don't really understand what the pump does. When the starter is hit, gas comes out of the fuel hose. How do I test the pump or bypass it? This thing is a pain in the butt.
 

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I’m not sure how to test the fuel pump. Although I know it’s vacuum actuated. So I think if the starter is cranking and fuel pluses out of the line, the pump is working to at least some extent.

As to the PRI setting on the petcock, what happens if you pull the line at the petcock and set it to PRI? I’m thinking it should dump gas all over if working correctly.

The pump is only needed because the lower portion of the tank is lower than the carburetor. It very low pressure. I agree both of these aspects of the fuel system seem to be overkill and needlessly problematic.
 

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The pump only needs to work when it's running. And should only work when turning over the engine.
I set the clip 2nd from the top.
The diaphragm went on mine too. I ended up getting a chinese and using the diaphragm out of it. Not perfect yet though. Good luck
 

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Discussion Starter · #29 ·
When you said your diaphragm went, can you explain? Did yours tear? Mine is in one piece, but needed help to stay in place long enough to get the cover on. I see where you can purchase just a chinese diagphram and slide. Also, manual says clip should be in the fourth spot. What made you go to the second spot?
 

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Discussion Starter · #32 ·
Ugh. This thing is driving me nuts. I replaced the slide diaphragm, no better. Quad was running like crap. It won't idle for more than 20 sec and it was bogging down with throttle. So....I am sort of starting over. I noticed that the intake boot to the cylinder has cracks at the base. I ordered a new one. But, when I removed it, the cracks do not appear to be all the way through. So, I will replace it anyway and see if it makes a difference, but not optimistic. I will also probably replace the vacuum lines. But, I need to know how to bypass the fuel pump to rule it out. How do I put a temporary gas tank up higher than the carb and just bypass the pump? Anybody do this or have any other suggestion?
 

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Ugh. This thing is driving me nuts. I replaced the slide diaphragm, no better. Quad was running like crap. It won't idle for more than 20 sec and it was bogging down with throttle. So....I am sort of starting over. I noticed that the intake boot to the cylinder has cracks at the base. I ordered a new one. But, when I removed it, the cracks do not appear to be all the way through. So, I will replace it anyway and see if it makes a difference, but not optimistic. I will also probably replace the vacuum lines. But, I need to know how to bypass the fuel pump to rule it out. How do I put a temporary gas tank up higher than the carb and just bypass the pump? Anybody do this or have any other suggestion?
You can just try a gravity feed with the fuel. Put a safe container with fuel above the machine and let it flow in.

After that, if you are still having trouble, let’s go back to basics.

At idle, try introducing a small amount of choke. Very small. As you increase the amount of choke, does it hold idle any better ? A restricted fuel passage will cause a lean condition that will correct itself by responding to the increased AFR caused by a choke closing.

Often you can clean a carb several times and still have an issue. I am hoping that is your problem. The fix maybe simple for you then.
 

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Discussion Starter · #37 ·
Update- the quad idles and runs absolutely perfect with a gravity feed. We have started looking into our vacuum system. We already had a brand new factory petcock to replace the aftermarket one that we got with the quad. In looking at the vacuum hoses and past posts, it appears we have the hoses in different locations. The bottom vacuum hose with the plastic fitting on the carb is currently going to the petcock and the metal fitting at top of carb is going to the fuel pump. This appears to be backwards from everybody else. Will this make a difference?
 

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Glad you got it all sorted out.
 
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