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Discussion Starter #1 (Edited by Moderator)
Hello everyone I am new to the forum. I am working a Suzuki King Quad 300 4X4 for a family member and I am dealing with several issues. First the atv has been in storage for several years. I had to buy a used fuel petcock for it and install it. It works great and the fuel pump is pumping fuel just fine. The atv has great spark no issues there. I pulled the carb off initially and cleaned it. The problem I am having is the King Quad is hard to start. I put in a new battery and it would take at least 2-3 minutes to start! Once I got it running it ran fine. Yesterday I removed the carb again and cleaned everything again and it is worse now. I had to turn the idle screw in the whole way for it to idle. Now it won't start or run unless I take the boot off between the carb and air box. And when you hit the top end of the throttle range it smokes really bad. I checked the intake boot and it does have some cracks in it but I sprayed starter fluid around it and nothing happened? I am not sure if the cracked intake boot would cause the carb to no operate properly or not? I tore the carb completely apart and cleaned all of the jets, air jets and made sure all carb passages were completely cleaned. I adjust the air/fuel mixture screw out 1.5 turns and tried it at 2 turns it didn't seen to make a difference in operation. I tried several times to reinstall the boot between the air box and carb and it shuts off immediately every time. I checked the air box, screen, and air intake tube for any obstructions and I did not find anything. I checked the choke function and it is working properly. I also double checked the jet placement and made sure I didn't switch the choke and main jet, no problems there. So I am at a lose now and need help desperately. I did check the air filter it is fine too. A local motorcycle mechanic said the intake boot has to be the culprit but before buying another one I need to find out if anyone else has suggestions on the matter. Thanks in advance for all of your help!
 

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Did you try taking the filter off then install the carb back on the intake boot? If it keeps running then put the filter back on if it dies then the filter is the problem. Or if you have a buddy with the same quad borrow theirs to see if you can duplicate the problem.
 

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My King Quad 300 takes a while to start too even on a warm day. I put it half choke then start it. Let it idle half choke for a few minutes then turn the choke off put it in gear right away then go. Give it a try.
 

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Discussion Starter #6
Ok, to answer the first question, I believe it is 1997 KQ. I got a used petcock for it and I have checked thoroughly, testing by removing the vacuum line and the diaphram quits working. So, i know the petcock is working properly. Onto the intake boot I did find the left machine screw was not turning in the whole way so I bought two new allen head bolts 6mmX1.5mm and was able to tighten the intake boot down. After doing that I was able to adjust the idle better but still not as much as it did when I initially got it running. Oh and now I can put on the boot from the carb to the airbox with the air filter inside and it will run through the gears without any hesitation or missing. The only problem that remains is the hard starting. I read an article that the fuel pump may be too weak. The quad has sat for about 5 years prior to me working on it. So I have no idea if the fuel pump is pumping enough pressure as it is? I have taken the fuel line off at the carb and hit the starter and the fuel delivery is not constant(like a garden host full blast) but oscillating(intermittant) with the cycling of the engine. I don't know anything about fuel pumps since all the quads and motorcycles I have worked on previously have been gravity feed? My next step would be to see if I can take the fuel pump apart and clean it. There was no gas in the tank when my friend brought it and it was clean in the bottom, the fuel petcock was clean when I bought it, the only doubt I have is the fuel pump itself. One more thing I did cover the intake boot in high temperature silicone and I let it fully cure(dry) to see if there were any air leaks in the intake boot. Of course that didn't seem to make a difference so I am taking it as there were no air leaks. Please if anyone has any more suggestions I would greatly appreciate them. My friends swear this thing was easy to start before. Oh you can't pull start it either the starter seems to be engaged when you pull the pull start cord? I am guessing the clutch that engages when the starter turns is either froze up from sitting around or needs replaced? Thanks again to everyone who replied so far for your time and to those who have any more ideas on the matter.
 

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First off the intake boot itself is not the problem air leaks on the intake side of the carb are not going to make any difference in how it runs... Take the cover off the air filter and remove air filter then install intake air boot to carb. it should run fine.. then install the air filter it should still run fine, now put cover on air filter if it then dies or won't start I would look at the air intake tube, if its like my 01 then there is ia rubber boot on the top of the air intake tube by the under the shifter lever covers. if that has worked loose and slid up it could be pressing against the top of the plastic cowling and not letting air in.. next look for obstruction in the air intake system like a mouse living in the tube somewhere...
the fuel pump only keeps fuel in the fuel bowl from your description it should not be and issue unless its pumping air into the fuel line which will cause carb to run rough. check fuel lines for cracks. I would clean up the fuel pump like you did the carb though
 

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Discussion Starter #9
Thanks again to everyone who replied to my post. I actually just got the King Quad back again. The "hard starting" issue is still not resolved. The quad actually just changed owners to another family member who thought they could fix it and they have given up. OK, here is what has been done since last time. The new owner installed a new piston and rings. When he put it back together he maid sure it was in time. We do not know if it was out of time before I never got that far when I gave up last time. So, now it has excellent compression, I checked the timing myself and made sure it is in proper time and it is. The new owner said it still is so hard to start and ended up burning the starter up because he couldn't get it to start. He did say that with the rubber boot from the carb to the airbox removed it would fire right up. It would run ok but of course without the airbox the upper rpm range would suffer. So, I adjusted the valves on it and I am waiting on the new starter to show up. I tried to start it with the pull start and it has excellent compression actually so much it is just too difficult to start with the pull start. I still don't understand why the boot from the carb to the airbox has to be off for it to start up? I tried connecting the airbox and rubber boot and removing the air filter but it still won't start. Once it starts up it will idle and run fine. You can put the boot back on between the airbox and carb and no problems. I ran it around for 30 minutes that way and shut if off and hit the starter button and it won't start again. Remove the boot from the airbox to the carb and it fires right back up? I was thinking fuel pump but I really have no idea? Would the fuel pump cause this? It is hard to start but once running it runs fine? I am at a loss on this one? HELP!! Anyone I am open to any suggestions. Once I get the new starter in I am going to clean the air filter and try that. I may end up having the new owner try an new intake boot and if that doesn't work a new fuel pump. After that I am not sure? I checked the spark again and it has good spark. Thanks again in advance of anyone with a similar machine or past experiece that can help.
 

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Discussion Starter #10
I should also add that I ran the VIN number and it is a 2000 King Quad 300 4X4, and not a 1997 like I previously thought. Sorry about that.
 

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Normally if you crank and crank on it usually indicates that the valves are just a touch out of adjustment, I would just loosen them just a quarter turn on the set screw tighten it back up and try it. If it doesn't fix the problem obviously you can change it back but it may be worth the 10 minutes to try and see if it fixes it.


THOMAS
 

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Discussion Starter #12
Thanks Tubbytubb. I did adjust the valves the other day. Unfortunately the owner burned up the starter and the compression is way to much for me to keep pull starting the quad. So, I will let you know if the valve adjustment did the trick when I get the new starter in. I did notice the exhaust valve had no tolerance and the intake valve was at .004. So I don't have a manual for a king quad but I do have one for several Yamaha 4X4 quads. They recommended .008 for the exhuast and .004 for the intake. I adjusted the valves to this and when pull starting it it seemed like it wanted to start. A sore arm made me give up but I am hopeful that this will solve the problem. Let me know if you or anyone else reading this post knows the actual setting for the valves for a King Quad? Thanks in advance if someone does post the correct tolerances. I also talked to the owner today and went over the quad. He did put a new fuel pump on, spark plug boot, and as previously mentioned rebuilt the top end with new rings and gaskets. I am running out of ideas as we are replacing items. We are down to replacing the intake boot and finally rebuilding the carb is none of the previous steps don't work? The spark is great no problems there. I will keep everyone posted. In the mean time please if anyone has those tolerances for the valve clearences reply with them. Thanks everyone again for all of your help.
 

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.003-.005 INT & .006-.008 EXH at least that is what the local dealer had told me on mine.



THOMAS
 

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Hey I meant to ask how many miles does your quad have on it, I learned something very important regarding the valves that could be causing the problem your having also. Also when you are turning it over does it look like fuel is spitting out of the back of the carb, away from the engine?


THOMAS
 

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Discussion Starter #16
Thomas,
I don't know because the previous owners grandchildren rolled the quad and broke the speedometer. Anyhow, I asked one of the grandchildren and he said he thought there were roughly 2000 miles on it when that happened. The new owner just rebuilt the top end. To answer your other question yes it does spit fuel out of the back of the carb when trying to start it. Let me know your thoughts? Thanks in advance.

Ryan
 

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You need to ask the new owner if he had done any work on the head (with the valves in it) if he didn't visually inspect the valve there may be a chance that the INTAKE valve is starting to wear and making it not seal properly and it will cause the adjustment on the valves to be constantly off if that is what is wrong with it.

You can see in the picture above that the valve head only has a single angle on it instead of the customary 3 angle (the reason for 3 angle valve job). This normally starts happening consistently around 2500 miles but depending on how it was ridden it could happen before then. This also would explain why it spits fuel out of the rear because the valve is not completely sealing the combustion chamber from the intake and the excess pressure is being released back through the carburetor and because the carb works off of a vacuum it makes it spit fuel out of the back. I cannot guarantee that this is what is causing your situation but there is, in my opinion, a strong possibility that it could be. The guy that does my machine work told me about this and he has been doing it for 15 years and he says every king quad he has worked on has had the exact same thing happen to it, odd thing is the exhaust valve is never effected like that they seem to last a whole lot longer without issues.



THOMAS
 

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Discussion Starter #18
Thomas,
Thanks! I never thought about the valve surface doing that and after looking at the picture you posted that makes sense. Ever since the previous owner got it out of storage it has spit fuel out of the back of the carb. I am going to put the new starter in tonight and see if it will fire up. If it doesn't which now knowing what you have told me I don't think it will I will have to look at the valves. I know for a fact the new owner did not do any valve work, just piston, rings and gaskets. Now if it is the intake valve can I replace it or do I have to have the valve seat resurfaced and lapped?
I have never done much with valve work other than adjusting them. So this will be a new experience for me. I do know that the quad was abused by the previous owners grandchildren. They never took good care of it and ran it very hard. Sorry just being honest here. I wish I knew the exact mileage like I said the one grandchild said it had around 2k on it when he rolled it and broke the speedometer. So I am guessing it started being hard to start when the other grand child worked on it and broke the fuel petcock and they gave up. Just a guess. Well let me know about the resurfacing and I will let you know how I make out with trying to start it tonight. The new owner did say that when he put new the new rings and gaskets in would fire up every time but after a while it became hard to start again. Thanks again! I really appreciate the information!
Ryan
 

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That will all depend on what it looks like when you get into it. I was lucky enough I didn't have to get mine resurfaced but I am assuming that is because the valve seats are harder than the valves which is a "good" thing and part of what causes it to happen. When you put the starter in tonight I bet if it doesn't start you can adjust the valves, I can tell you a fast and easy way to get a rough set on them to keep from having to break out the feeler gauges, and it will crank right up and run for a little while but then after it warms up it probably won't crank back up. Let me know how it goes and I will do what I can to help you out on getting it fixed.



THOMAS
 

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Discussion Starter #20
Well tonight was uneventful because the starter clutch kept slipping. The new starter kept turning and the engine wouldnt turn over. So I called the owner and he said he had this apart during the rebuild. He also said there were pieces laying in the case and they put them back in place. I will have to take the cover off and see what is going on? I'm willing to bet something isn't in the right place or the starter clutch is shot? I also noticed when I try and pull start it the starter turns also? It sounds like the starter clutch is engaged all of the time? One other thing should it have so much compression I can barely pull start it?
 
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