Suzuki king quad 300 idles great but Boggs when you apply throttle

[97kingquad]

Lol you guys kinda crack me up 

[Gwbarm]

I have went back through all the posts, it took a minute or two, you have done quite a bit of work to the carb with no change, changed needle positions , cleaned carb a multitude of times, there should have at least been a noticable change, if not better, worse. Im not convinced this is a carb problem, but it could be. On rare occasions i have had a carb that no matter how many times i cleaned it  just would never run exactly right, until i replaced the carb, still dont know what the problem was. To check it, do you have a carb from your parts bike you can clean put on to try. Just a thought. Also have you checked the compression, the engine sounds really good i dont expect to see a problem there but it might be worth checking. Im also thinking about the pickup coil i know its working and they usually either work or dont work, but because of your continued problem i might check that over really good again, connections, resistances and maybe even inspect for wires that may be loose and not keeping up with spark on the higher RPMs. Im just hashing everything over in my mind trying to think of options that might be causing this. 

[97kingquad]

31 minutes ago, Gwbarm said:

I have went back through all the posts, it took a minute or two, you have done quite a bit of work to the carb with no change, changed needle positions , cleaned carb a multitude of times, there should have at least been a noticable change, if not better, worse. Im not convinced this is a carb problem, but it could be. On rare occasions i have had a carb that no matter how many times i cleaned it  just would never run exactly right, until i replaced the carb, still dont know what the problem was. To check it, do you have a carb from your parts bike you can clean put on to try. Just a thought. Also have you checked the compression, the engine sounds really good i dont expect to see a problem there but it might be worth checking. Im also thinking about the pickup coil i know its working and they usually either work or dont work, but because of your continued problem i might check that over really good again, connections, resistances and maybe even inspect for wires that may be loose and not keeping up with spark on the higher RPMs. Im just hashing everything over in my mind trying to think of options that might be causing this. 

I need to look into the Jets I may have missed first. I didnt have a carb diagram until yesterday so I am disassembling the entire thing and putting it all back together first and compression is good. Coil has been replaced as well as the rectifier I will let you know once I get the last pieces out cleaned and put back in today (I'm going to get the safety torch bit now to disassemble the slider now) I will update shortly 

[Gwbarm]

Good plan, I would check for numbers on the jets to make sure they are correct and get the emulsion tube out to clean it that was part#6 and go from there.

[JustRandy]

58 minutes ago, Gwbarm said:

you have done quite a bit of work to the carb with no change, changed needle positions , cleaned carb a multitude of times, there should have at least been a noticable change

Yep that's what I was thinking in the beginning.  If adjusting the needle up and down doesn't change anything then it's something else.  I'm watching and waiting until a valve check is finally performed.  Intake valve and regulator are notorious faults on these quads and should be ruled out first thing.

1 hour ago, Gwbarm said:

Also have you checked the compression, the engine sounds really good i dont expect to see a problem there but it might be worth checking.

These engines have such a long stroke compared to the bore that even a low compression engine will still run good.  A friend had a 250s, which is the exact same piston but shorter stroke, and the kicker would just about fall under its own weight it had so little compression.  It smoked like a tar pit but ran like a raped ape.

If the intake valve is open the loss of compression wouldn't affect it much except for it firing back into the cv carb.  If he had a mechanical carb the symptoms would be less dramatic.  Also removing the airbox lid would relieve some of the backfire pressure and keep the slide from fluttering as much.

And running better with a dead battery implicates the regulator.  I'd hookup a voltmeter and be sure the volts never exceed 14.4 at any rpm. Swapping regulators with another used one wouldn't necessarily rule it out since both could be bad.  I swapped in a LT4WD regulator when my king regulator failed.  Not long after the one I swapped also failed.

[97kingquad]

42 minutes ago, JustRandy said:

Yep that's what I was thinking in the beginning.  If adjusting the needle up and down doesn't change anything then it's something else.  I'm watching and waiting until a valve check is finally performed.  Intake valve and regulator are notorious faults on these quads and should be ruled out first thing.

These engines have such a long stroke compared to the bore that even a low compression engine will still run good.  A friend had a 250s, which is the exact same piston but shorter stroke, and the kicker would just about fall under its own weight it had so little compression.  It smoked like a tar pit but ran like a raped ape.

If the intake valve is open the loss of compression wouldn't affect it much except for it firing back into the cv carb.  If he had a mechanical carb the symptoms would be less dramatic.  Also removing the airbox lid would relieve some of the backfire pressure and keep the slide from fluttering as much.

And running better with a dead battery implicates the regulator.  I'd hookup a voltmeter and be sure the volts never exceed 14.4 at any rpm. Swapping regulators with another used one wouldn't necessarily rule it out since both could be bad.  I swapped in a LT4WD regulator when my king regulator failed.  Not long after the one I swapped also failed.

I didn't say it runs better with a dead battery when I started the thread I said it ran fine before even with the dead battery 

Also I may have made some progress, there was some crap the pin hole of the slider jet so I cleaned that out and now I can get about half throttle with everything sealed properly so now I'm adjusting my set screw to see if I can get it to hit at least ¾ throttle 

[JustRandy]

On 7/23/2023 at 6:23 PM, 97kingquad said:

It ran great for a few days and now it will only idle if I rec it up it Boggs and dies if I don't flutter the throttle. 

My battery was dead before when it ran well also and it doesn't change when using a booster pack.

To me that sounds like it ran well when the battery was dead.

It seems like it would be really easy to hook up a voltmeter to the battery and observe the voltage while you rev it up like in the video.  That would officially rule out the regulator.

The screw you're turning only affects the idle, so if there is any improvement it's only a coincidence.  It could be that the engine is getting warmer or the weather is changing.

 

[97kingquad]

35 minutes ago, JustRandy said:

To me that sounds like it ran well when the battery was dead.

It seems like it would be really easy to hook up a voltmeter to the battery and observe the voltage while you rev it up like in the video.  That would officially rule out the regulator.

The screw you're turning only affects the idle, so if there is any improvement it's only a coincidence.  It could be that the engine is getting warmer or the weather is changing.

 

The screw I am turning is the fuel set screw restricts the flow, what one is the main jet off the carb diagram?

36 minutes ago, JustRandy said:

To me that sounds like it ran well when the battery was dead.

It seems like it would be really easy to hook up a voltmeter to the battery and observe the voltage while you rev it up like in the video.  That would officially rule out the regulator.

The screw you're turning only affects the idle, so if there is any improvement it's only a coincidence.  It could be that the engine is getting warmer or the weather is changing.

 

I have hooked voltmeter to it and it gets around 14.2 when I peak the throttle without the airbox cover on so I can hit higher rpm. 

Around 11-13 or so idling 

[JustRandy]

9 minutes ago, 97kingquad said:

The screw I am turning is the fuel set screw restricts the flow, what one is the main jet off the carb diagram?

The only screws I'm aware of on any carb are the idle mixture screw (#14) and idle speed screw (#28).  The main jet is #17 on the diagram and isn't adjustable.  The pilot jet is #15.

9 minutes ago, 97kingquad said:

I have hooked voltmeter to it and it gets around 14.2 when I peak the throttle without the airbox cover on so I can hit higher rpm. 

Around 11-13 or so idling 

I guess as long as the voltage doesn't go over 15 the CDI should still function.

I guess we can rule out the regulator as the cause of the problem, but because the idle voltage is so low I'm not sure we can say the regulator is good.

[Mech]

97.. try pulling on the pull start. You will feel compression bring it to a stop, or feel it creep over easy if a valve is leaking or the compression is low.. but I doubt it is because you say it idles nice.

Try the two spark plug test to see if the spark fails at revs, but I doubt it because the symptoms don't indicate that.

The backfiring isn't the idle mixture, if you opened the throttle to 1/2 like I said to and it backfires into the airbox then it's the carb aand needle or fuel supply.

To test the fuel pump you lay the fuel hose to the carb into a bottle. Lay it on it's side with the hose laying flat. If the hose is dangling down you won't see the fuel pumping out properly. Then suck hard two or three times on the vacuum hose going to the pump, and then let the vacuum off suddenly. You should see a single slug of fuel come out of the fuel hose. The slug should be full diameter of the hose and about ten mills long. If that works then your pump is ok and will work if it's getting good pulsating vacuuum.

To test the vacuum you reattach the vacuum hose and start the motor and let it idle. It should pump fuel out of the fuel hose into the bottle at full diameter of the hose and slugs about eight mills long. If that works then the pump is working and it should start and idle at east.

Then you need to check the vacuum is still strong enough when the motor is under load. To check that you leave it all as is but sit on the bike, put the brakes on hard, engage first gear and open the throttle until the motor starts straining against the centrifugal clutch. As the motor starts to labour the pump will likely slow down it's delivery of fuel, but it should keep pumping some. If it stops pumping then you have weak vacuum or a malfunctioning pump.

The vacuum has to be strong, and pulsating when it gets to the pump. If the vacuum hose has been swapped with some soft thin walled stuff the pulsations can get lost as they suck the vacuum hose flat and then let it out again. Low vacuum can be caused by low compression, tight valves, or air leaks. Low vacuum at high revs can be caused by a blocked exhaust.

 

Edited July 29, 2023 by Mech

[Mech]

And you need to blow through the jets 97, not flush them in chemicals. In fact, degreasing parts, and parts in degreaser, is just asking for problems. Metal gets a patina on it that stops it getting rust or corroding and if we take that off they corrode. In the case of aluminum and brass together there potential for an electrolysis reaction as well and you should make sure you spray something like crc 565 or wd40 on the parts after cleaning them.

Take every jet you can out and blow through it, just your breath will do, then hold it up to the light. The hole should be obvious and appear nice and round. If it's not nice and round or if you suspect it's still dirty then whittle a small bit of hard wood down to a fine point and use that to ream the holes a little then blow them and reinspect them. That's all they need.

If you have compresed air, blow gently through all the carb body passages gently to trace where they go, and then blow them backwards to their normal direction of flow with a hard blast of air. Don't blow hard in the normal direction or air flow or especially fuel flow, or you might cause a tight blockage where there was only an obstruction before,

In the case of that No6, the tiny holes in the side are arranged opposite one other so you can see through both at once. They are too small for a bit of wood and you don't want to block them so use a single strand of wire from a wire brush to carefully poke through them if it fits easily, and then rotate the wire to rub the sides of the holes carefully then blow them out.. Don't damage the holes or enlarge them. Also, the hole that No6 fits into needs to be clean, check it for corrosion buildup on it's walls. Use a small bit of wood or something to rub up there if needed. It's a calibrated quantity of fuel in there and so that hole has to be clean to hold the right amount. 

 

[Mech]

Oh.. when you are testing the fuel pump by sucking on the vacuum hose, you need to have the fuel tap in the prime position.. I forgot to mention that.. 

[97kingquad]

Thanks mech I read all of that and I will check everything but I found something...

I did see through all the jet holes and they were nice and clean. But maybe this could be an issue lol

2 minutes ago, Mech said:

Oh.. when you are testing the fuel pump by sucking on the vacuum hose, you need to have the fuel tap in the prime position.. I forgot to mention that.. 

 

[JustRandy]

3 minutes ago, 97kingquad said:

Thanks mech I read all of that and I will check everything but I found something...

I did see through all the jet holes and they were nice and clean. But maybe this could be an issue lol

 

I told you it's worth your time to tear the pump down because of the corrosion I found in mine.  Mech ridiculed me for it.

On 7/26/2023 at 1:31 AM, Mech said:

What ? Because you have a pump with a bit of corrosion in it, everyone should take theirs apart ?

 

[97kingquad]

4 minutes ago, JustRandy said:

I told you it's worth your time to tear the pump down because of the corrosion I found in mine.  Mech ridiculed me for it.

 

I told you I was going to go through everything anyway 

[JustRandy]

1 minute ago, 97kingquad said:

I told you I was going to go through everything anyway 

But you do see the ridicule, right?  That's what started all the fighting.

[Mech]

I would have tested that before pulling it to bits. It was probably working fine. Now that you have pulled it to bits it's important as you put it together that you assemble it so the diaphragm has some flex availiable to it. If you just put the diaphragm in and do the screws up with only the spring deflecting the diaphragm it might not have enough movement to work well. You assemble it, do the screws just barely tight enough to hold the parts together and then you apply vacuum to it to deflect the diaphragm. If you are doing it right you will probably, and hope to see, the edges of the diaphragm pull in slightly. If they don't, then loosen the screws a tiny amount. You should be able to suck it and see the edges move, then tighten the screws with the edges pulled in as much as possible.

Like a petulant child....  What happens in a persons life to make them so angry about everything..  So defensive

I think it's sad It's self limiting, and self destructive as far as I can see, and does nobody any good..   But hey, what would I know.... 

[JustRandy]

And where is the clear plastic membrane?  And the valve?

I don't see them here:

[97kingquad]

22 minutes ago, JustRandy said:

And where is the clear plastic membrane?  And the valve?

I don't see them here:

This is the assembly my parts bike and my bike had. No clear plastic but there are two gaskets 

[Gwbarm]

Attached to the cover still upper right

[97kingquad]

1 minute ago, Gwbarm said:

Attached to the cover still upper right

There's no clear plastic section on either of mine 

[Gwbarm]

Sorry i guess its the way the light was hitting it kind of shiny like plastic

[Mech]

97.. if your pump is still on the bike just test it.

If you change too many things at a time without testing your steps as you go you will just introduce a lot of complications.. And goodness knows there's been enough of them already..

This diagnosis should be a simple and straight forwards process..

[JustRandy]

Just now, 97kingquad said:

There's no clear plastic section on either of mine 

Wow that's odd.  The plastic is what seals the pump from the engine vacuum.  Do you know what years your are?  Mine is 1998.

[Mech]

There's a diaphragm there 97..  Don't worry about that. It's just a distraction. You're being led astray.

Just go test your other pump on the bike.

[Mech]

If that's the pump off your bike put it back together.. 

This is getting ridiculous.

[JustRandy]

What about the little one-way valve?

 

[Mech]

I'll check in in a while 97..  Please listen to what I'm saying.. 

[97kingquad]

54 minutes ago, JustRandy said:

Wow that's odd.  The plastic is what seals the pump from the engine vacuum.  Do you know what years your are?  Mine is 1998.

Mine is a 97

[97kingquad]

55 minutes ago, Mech said:

97.. if your pump is still on the bike just test it.

If you change too many things at a time without testing your steps as you go you will just introduce a lot of complications.. And goodness knows there's been enough of them already..

This diagnosis should be a simple and straight forwards process..

Ok so I appreciate your help and everyone else on here (including you randy) but mech I am going to go over everything on the bike anyway, it is running much better after cleaning the pump. I need a new one but the one on my parts bike cleaned up nicer and was the same numbers so I swapped it. I need to get a new pump though. And I am meeting a guy tonight that might have a carb off same year bike. He bought for the Axles 

The pump was in terrible shape. This one's not much better but better still and by the improvement I think it may be a big part of the issue. It only Boggs at half throttle (possibly due to the corroded pump) which looked new on the outside but was very rusted inside. 

I can drive it around and it is still a little peppy but won't go over half throttle. If I hold it just under I can cruise around and go through the gears fine but more and it Boggs.

I appologize there is a lot of stuff that happens between what I post so it can get confusing for you all. I am following what tips you guys give me but at the end of the day I am going to do what I feel is the best approach. When I try something or switch something I test it as well and check that there is an improvement or not if not I put the original back on and move on. I have fixed a few other quirks along the way 

56 minutes ago, Mech said:

If that's the pump off your bike put it back together.. 

This is getting ridiculous.

It is the pump off my bike and it looks like crap so I am going to clean it up and get a new one