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Discussion Starter · #1 ·
I just purchased a 2020 King Quad 750 with 100 miles on it. After riding it around for a bit I noticed that if I slow down to a crawl or come to a stop it starts bogging down and wants to stall. I can keep it running only if I feather the throttle. Once I get moving again it seems to be just fine. If it stalls out, when I try restarting it it starts and then stalls again. The only way I can start it is by giving it a little gas as I hit the start button. Any thoughts on what the problem may be? Like I said, it only has 100 miles on it but it has 50 hrs which tells me that either it has spent considerable time just idling or was babied the first 100 miles. I verified that the voltage regulator is working correctly and I also put the quad into dealer mode and verified the TPS position. Mine is COO-. I did notice that the dashed line moves up when I hit the throttle, is this normal? I verified the TPS position with both a cold motor and warm motor.

I've read several accounts where people have put different fuel pumps on these and even a different fuel injector. I have a hard time believing that the fuel injector or fuel pump is bad given the low miles on this machine. Any help or insight would be much appreciated.
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I just purchased a 2020 King Quad 750 with 100 miles on it. After riding it around for a bit I noticed that if I slow down to a crawl or come to a stop it starts bogging down and wants to stall. I can keep it running only if I feather the throttle. Once I get moving again it seems to be just fine. If it stalls out, when I try restarting it it starts and then stalls again. The only way I can start it is by giving it a little gas as I hit the start button. Any thoughts on what the problem may be? Like I said, it only has 100 miles on it but it has 50 hrs which tells me that either it has spent considerable time just idling or was babied the first 100 miles. I verified that the voltage regulator is working correctly and I also put the quad into dealer mode and verified the TPS position. Mine is COO-. I did notice that the dashed line moves up when I hit the throttle, is this normal? I verified the TPS position with both a cold motor and warm motor.

I've read several accounts where people have put different fuel pumps on these and even a different fuel injector. I have a hard time believing that the fuel injector or fuel pump is bad given the low miles on this machine. Any help or insight would be much appreciated.
View attachment 21120

Welcome to the forum.

Did you purchase it from a dealer? Is this machine still under warranty?

How does the fuel smell?

Give us a little history on it. Perhaps we can help.
 

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Is it stalling in Neutral? Or does it idle just fine in neutral and only when you put it in gear it seems to bog and stall? If it does that, then I would suspect clutch is dragging.

If it stalls in neutral, then it most likely is a weak fuel pump or weak battery.
 

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Discussion Starter · #4 ·
I purchased this from a private party. The first thing I did after I purchased it was put fresh rec fuel in it. I rode it around for a little while yesterday and it ran great for about 10 minutes. Then it started bogging and wanting to stall. Almost seemed to be starving for fuel. If I let it sit an idle it will stall out after about 15 seconds. I rode it the entire time with it in "dealer mode" and the TPS sensor seems to be working fine.
 

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My only issue with Suzuki quads has been their lack of electrical power. They put small stators in them and it is basically just enough to run the stock quad.

I found this out on my 500 King Quad with EPS. If I'm using the winch at the same time I try to turn, the EPS, Winch, and Fuel pump are just to much for the system and if the battery is weak, the machine will die.
For that reason, in the winter I put a car battery on the back rack and plug it in. I have a battery maintainer on it, so I just plug it in most of the time in the winter.

I believe the stator on these are just 180 watts, so having a good battery is critical to keep the fuel pump flowing properly. The electronics are not sophisticated enough to prioritize individual components, which would be ideal.
 

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Discussion Starter · #6 ·
Thanks for the reply. Ya, my quad will stall out when it is idling in neutral. I'm pretty sure the battery is good, I didn't throw any red flags when I was checking the voltage. If I remember right it was at around 12.6 volts with the key off and 14.6 volts while running. Voltage never fluctuated more than 0.1 volts even when I revved the engine. Headlights seem bright, they do not flicker or get dim.

I'm leaning towards a fuel pump issue. What I don't understand is why it runs great for 10 minutes. If it was the fuel pump, I would think that it would run like crap all the time. I have ridden the quad several times now and EVERY time it runs great for the first 10 minutes or so and then it starts having issues with bogging down and stalling. The longer I continue to ride the worse the issues seem to get. If I shut it down and let it sit for 20-30 minutes, it runs great again for 10 minutes.
 

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I would pop the seat off and feel the ECU to verify it isn’t getting too hot. If you have a thermal gun, check it in the shade before you start the engine, then after 5-10 minutes, then immediately after it starts running bad, then again as it runs worse.

I wouldn’t expect a bad ECU on a 2020, but it almost sounds like something is going thermal. How does the fuel pump sound when you turn the key to the on position before you start the engine?
 

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Discussion Starter · #8 ·
Fuel pump sounds fine. Runs for a few seconds then turns off. I agree, definitely seems to be something thermal. I'll check the ECU when I get home on Thursday. Thanks!
 

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Fuel pump sounds fine. Runs for a few seconds then turns off. I agree, definitely seems to be something thermal. I'll check the ECU when I get home on Thursday. Thanks!
Let us know what you find. Good luck with it .
 

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Its like the fuel lines are getting to hot and its vaporizers and starves for fuel. Then you let it cool down and it runs fine until nthe fuel lines heat up again...
 
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