lanow

Suzuki King Quad 300 Running Problems

14 posts in this topic

Hi Everyone,

I am new to this forum and hope that someone out there can help me, I have an early Suzuki King Quad 300 (280cc) which starts intstantly every time but at about half revs or there abouts it starts spluttering and will not rev any higher, this fault is present whether choke is applied or not, some one suggested that silencer maybe be clogged so removed baffle but no improvement have removed carb and stripped 3 times but still no joy.

Any ideas would be most welcome.

Cheers Rob

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unplug rev. switch try again. check air filter, Check ALL carb vacuum ports and lines including tank vent are clear,Clean carb 4th time , Just a few houghts good luck

Edited by racers

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fuel tank petcock diagram is broken. and sucking fuel as some as you rev it. check it for a rip or whole. common problem. easy fix is to block the vacuum line. the side fuel pump is good enough.

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What year is it? Sounds like the bowl is starving for gas and full throttle.

* Re-worded title for searched. Added issue.

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What year is it? Sounds like the bowl is starving for gas and full throttle.

* Re-worded title for searched. Added issue.

Same problem here. I believe its electrical though. If I hold the starter button down and rev the bike it revs up fine. Sometimes it will start and rev fine for a few minutes and other times it will rev once and then act like its a limiter. I seen you posted to disconnect the rev wire. Where about is this located? I didnt see any safety switches to trace back. Thanks

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So after messing around with the atv I found that if I turned the igntion forward another click so the headlights would come on it would stop stumbling. Took it out for a test drive and it started the problem again. Changed the ignition which did not help. Checked charging found that its charging at 17 volts. Looks like regulator rectifier. I"ll let you know as soon as I swap it out.

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So after messing around with the atv I found that if I turned the igntion forward another click so the headlights would come on it would stop stumbling. Took it out for a test drive and it started the problem again. Changed the ignition which did not help. Checked charging found that its charging at 17 volts. Looks like regulator rectifier. I"ll let you know as soon as I swap it out.

Good to hear you have a direction and diagnosis made! :yes: Good Luck!

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Hello. This is a neat little forum and every thread I see has replies with reasonable answers, so I signed up in hopes of getting to the bottom of my 300 king quad problems :) I was using another forum, but it seems I'm the only guy answering questions over there lol. Anyway, I'm having trouble similar to the OP. It just seems the carb isn't getting enough gas.

Thanks to oxidized_black, I was able to get the service manual and I set the float just over .5 inch (It was way high). I noticed when I pressed on the float, before it used up the spring inside the needle, the float would hit the carb body. That didn't seem right to me so I left it at that setting without going fully to .5 inches as the spec said. I've also installed a 40 pilot jet in place of the 37.5. I've installed a 140 main in place of the 120 something. Needle clip is per spec at 4 clip from top. All these specs seem odd to me. Usually carbs are set at 3rd clip (middle one) and mixture screw is 1.5 turns out instead of 2 5/8 like the spec says.

So even with all this richening, I'm still having to use the choke to idle and oddly enough, I'm having to use it more the hotter the engine gets! Which is making me think its something electrical. Only electrical things crap out with heat. But what could it be? And sometimes it will rev out nicely. Then I head for the road to see how fast it will go and it acts like the road scares it LOL! It acts like its out of gas. So I limp back to the yard fearing I'll be stranded on the road and it runs good again as soon as it hits grass. I'm baffled.

I had the petcock problem everyone else had and I bypassed that. I took the fuel pump apart and polished the corrosion off. There's no reason the pump shouldn't be working right.

Valves are set right, but engine is full of gas due to the petcock problem. Its not insanely full, but it is overfull. I've read this can cause problems, but its hard for me to imagine it would cause an engine to run lean. I don't want to drain it and refill because as soon as I get it running right, I'm tearing the engine apart. IE I don't want to waste 4qts of oil. Unless someone really really thinks it could cause big problems. I don't want to break in a new engine with carb problems.

Thoughts?

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PM Cheriah as she is the official QC carb queen. She might be able to steer you in the right direction

Sent from my SGH-T989 using Xparent Blue Tapatalk 2

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Update. My regulator was bad. Big crack in the back and bulging out. I swaped it. Now I have 14.3 volts, but no change in how it runs.

Ignition coil was at lower end of where it should be on ohms, but close enough I guess. I cleaned the grounding points.

I pulled that silly rubber strap off my gas cap and verified I have a good hole there so the tank doesn't develop a vacuum.

It seem nothing I do will produce a change in how it runs. Big jets, little jets,,,, it doesn't matter. Choke is always needed and sometimes it will rev and sometimes not. Sometimes it will idle nicely and then I sit down and just wait. A few min will pass and it will get slower and slower until it dies. Makes me think its rich. Well, why does the choke make it run better?

I need a priest. This thing is possessed or something.

Its funny because I'm usually the carb guy. I can take a bare carb body and figure out what fuel jets, air jets, needles, and slides work and do it with no airbox! I don't like to pat myself on the back, but just throwing that out there. This really has me puzzled though. I'm about to set a tank on the rack and gravity feed a regular carb just to see. I usually respect japanese engineering but those guys must have been hittin the saki hard when they came up with this!

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I put a 26mm roundslide from a 230 quadsport on and gravity feed tank and it runs like a champ. I spent the day seeing what all this machine will pull lol. I guess I need to find a 28mm carb somewhere. That's probably about right for this engine. This is just another reason why I hate CV carbs. Too many things to go wrong with them.

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Is any one on here to help me on my 300 king quad it runs at a idle n revs at first then go to spuddering I can turn it off n back on n it runs fine then starts spuddering I have cleaned carb n all hoses n put a carb kit n and no luck any suggestions

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heres a little trick I figured out for hard starting atvs that seem to run but shut down and sputter out. If your having Backfiring through the carb, spitting gas out through the carb it maybe a bad intake valve not seating properly. To test this Pull spark plug out, move piston to TDC on compression stroke, Take some compressed air with a air nozzle in spark plug hole, make sure you can seal it to the hole so no air can escape. apply the air and listen for air escaping through the carb or the exhaust valves. that will determine if you have a bad valve. Best way to check for bad valves.

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