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Thread: Kawasaki (carb problem) Gurus please help!

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    Question Kawasaki (carb problem) Gurus please help!

    I recently had a '97 Bayou 300 4X4 4 stroke basically dropped in my lap. I am about to pull my hair out because of it(no wonder it was such a great deal). The previous owner said it started acting up so he parked it since he had other wheelers to use. It sat for about a year. He described the problem as backfiring through the carb and dying especially at idle. When I got it home I: put in new battery, removed and cleaned gas tank, removed and rebuilt carb, checked timing chain, checked valve play, tested spark.
    Here's the problem/s and for all these it doesn't matter if it is warmed up or not (outside temp 65F): 1/2 the time it will start without choke on, 1/2 the time has to be choked. Sometimes it will fire up right away other times you have to crank over and over up to a minute (in about 6-8 second tries). When it does start, sometimes it idles fine others you have to turn the idle way up to keep it running. Sometimes when you touch the throttle it will pop through the carb and then sputter until it dies other times it accelerates just fine. Part of the time it will hold higher RPMs with the throttle fine others it will again sputter and die. When it does die it still goes back to the 1/2 and 1/2 choke problem and the start/not start right away problem. The times that I can keep it running, if I give it 1/2 to full throttle the exhaust it a brownish color. I check the spark plug (several new ones) and they come out of the engine with a very little black color except for the electrodes which are the same metallic color as a new unused one.

    I am open to any suggestions and am more than willing to buy a beer (or six) for the person who gives me the cure that fixes the wheeler. (and replacing the whole thing isn't a fix, that's just passing off the problem)

    Thank you in advance,
    Tom

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    Member BIGAKSTUFF's Avatar
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    Sounds like its still a carb issue to me, but the brown exhaust sounds like a mixture problem, so maybe you got two problems going on at once here? That carb sat for a year, and who knows how long it was jacked up before the last guy tried to get it going. When you rebuilt the carb, did the kit come with new jets, and did you use them? Also, check the factory setting for the clip on your main jet, somebody else may of rebuilt the carb and put it back on on the wrong level.

    The last time I had carb problems on my rancher 350, I rebuilt it, and still had no joy. So I took the whole thing apart and completley submerged all the parts in a carb cleaning solvent ALL NIGHT, blew it out the next day, reassembled, and it worked like a charm. I'm no gear head, but I have had my fair share of carb issues on wheelers, what your describing with the sputtering and intermittent running sounds like a piece of crap in your carb.

    Check ebay for a replacement carb, you can find em cheap these days.....
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    It came with 2 jets in the kit and I also got a new diaphragm. The guy said his kid had rebuilt it once before but didn't mention if before or after the problems. I'm not sure what you mean by the "clip" for the main jet. I got it sitting apart right now and I will look for a clip on a jet. I used new gas to clean it, guess I will get some cleaner to soak it in before reassembly.

    I checked into Ebay for a replacement carb and I was hoping to get it done with a rebuild and tune before going that route. Would really hate to get one online, put in on and have the same problem and be out the additional $$ and have 2 junk carbs on my hands. Or get another carb and have it be something totally different.

    Thanks for the reply and I will post my findings after trying your suggestions.

    Tom

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    Quote Originally Posted by dandeo2003 View Post
    It came with 2 jets in the kit and I also got a new diaphragm. The guy said his kid had rebuilt it once before but didn't mention if before or after the problems. I'm not sure what you mean by the "clip" for the main jet. I got it sitting apart right now and I will look for a clip on a jet. I used new gas to clean it, guess I will get some cleaner to soak it in before reassembly.

    I checked into Ebay for a replacement carb and I was hoping to get it done with a rebuild and tune before going that route. Would really hate to get one online, put in on and have the same problem and be out the additional $$ and have 2 junk carbs on my hands. Or get another carb and have it be something totally different.

    Thanks for the reply and I will post my findings after trying your suggestions.

    Tom
    I'm sorry, said the wrong part, the float needle, not the main jet! At the top of the needle there are grooves that slide into a clip for different heights varying how high your float will go, now I'm going on what i have seen in honda carbs, but can't imagine a Kawa can be much different. You can't know for sure if the kid rebuilt it right, so look that up.

    Yes, you need something INDUSTRIAL to get that gunk out of there, regular old gasoline probably wont cut it. A spray carb cleaner is what I normally use and it does the trick, but soaking it over night will be best for one thats sat for so long. The fuel these days eats carbs up by just sitting inside for long periods of time, its a pain in the butt.
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    Well the carb IS used by both Kawa and Honda. I'll check the float needle to see if it is adjustable. I do know that the float seat is permanent and not replaceable according to everything I've read about this particular carb.

    Tom

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    OK so I got some good carb cleaner and cleaned out the carb. The float needle is not adjustable with the exception of adjusting float level. Put it back together with the idle screw set at 2 turns as I've been told it should be. Started it up and same thing as usual. I did manage to keep it running for a little bit. When it died I pulled the plug and it was looking lean so I adjusted another 1/2 turn. Got it to start back up with a new plug same result. I adjusted the screw another 1/2 turn (now at 3 full turns) and tried again. Idled really low, even though the throttle adjust screw was turned up. I revved the engine holding it at about 2/3 throttle and at least it didn't spit and pop through the carb but when I let off the throttle it went down to about 1/4 throttle and the RPMs stayed there until I bumped the throttle then it dropped to a really low idle and then once again it died. I pulled the plug and it is perfect looking (not rich/not lean). I have a feeling it just needs to be used as an one time anchor and I should go back to 2 strokes again! Never owned a Kawasaki before and am starting to think that if this is the norm I shouldn't have started.

    Tom

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    How are you determining the float level setting? Did you flow check the carb? Is it just gravity feed or is there a fuel pump? If you have compression and spark; you should be able to get the fuel / air mixture to stoichiometric. 12 or 13 parts air to one part fuel. Make sure after you check the carb float setting that the only air getting to the cylinder is through the carb intake. No intake air leaks.

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    I set the float with a template in the rebuild kit. Not sure what you mean by "flow check" the carb. It is gravity fed, and I have tried all of this with the fuel cap both on and off with no change in the way it acts between the two. I have checked for air leaks each time I put the carb back in by spraying from where intake meets the head all the way to the airbox by spraying it with starting fluid while it is running.

    Last night I got it to at least not pop or backfire through the carb but it still won't idle correctly and dies like it ran out of fuel when you let off the throttle. Holding the throttle at high RPMs and let off it drops down to a low idle(even though throttle adjust is turned up to help keep it running) and then it stalls out.

    I will recheck the float level today. Does anyone know if someone in the Wasilla store sells those see through fuel level gauges for checking float level?

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    Quote Originally Posted by dandeo2003 View Post
    OK so I got some good carb cleaner and cleaned out the carb. The float needle is not adjustable with the exception of adjusting float level. Put it back together with the idle screw set at 2 turns as I've been told it should be. Started it up and same thing as usual. I did manage to keep it running for a little bit. When it died I pulled the plug and it was looking lean so I adjusted another 1/2 turn. Got it to start back up with a new plug same result. I adjusted the screw another 1/2 turn (now at 3 full turns) and tried again. Idled really low, even though the throttle adjust screw was turned up. I revved the engine holding it at about 2/3 throttle and at least it didn't spit and pop through the carb but when I let off the throttle it went down to about 1/4 throttle and the RPMs stayed there until I bumped the throttle then it dropped to a really low idle and then once again it died. I pulled the plug and it is perfect looking (not rich/not lean). I have a feeling it just needs to be used as an one time anchor and I should go back to 2 strokes again! Never owned a Kawasaki before and am starting to think that if this is the norm I shouldn't have started.

    Tom
    Man, I understand your fustration, but don't sink her! lol. I am sure you know this, but just in case.... When you adjusted the screw 2 turns - you bottomed it out first, then BACKED it out 2 turns, correct?

    Only other suggestions I have are to check your fuel lines for leaks/blockage. Does it have a inline fuel filter installed? People will install them aftermarket (i've done it myself) and they can clog up restricting fuel flow to your carb.

    I doubt this is the problem, but clean your air filter out as well. Good luck
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    I would check compression, sounds like you may have a valve not seating.
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    Big: lightly seated then back out the 2 turns then out an additional turn to not look like it's running lean. Do you suggest I go further and try a little on the rich side? I have checked the fuel line and I am the one who installed an inline fuel filter. It is clear/see through and I see no visible "dirt" in it(better not after cleaning the tank and petcock twice). I will try cleaning the air filter although it does appear "newish" meaning it doesn't even have dust on it. Since I'm not seeing any dirt in the fuel filter I think I'll try a new piece of line without a filter too.

    Stid: No I haven't checked compression yet. I did check the valve clearance at the rockers and it was dead on center of tolerance. I'll see if my brother - in - law has a compression guage that will fit it.

    What I am currently confused about is why the thing won't idle right. If I start it, it will idle REALLY low then die sounding like it is starving for fuel. Start it back up and adjust the throttle setting and it will idle at an acceptable level. At this point I can let it sit for over 5 minutes and it will keep running except the RPMs will slowly rise and fall approx. a couple hundred. Then I can hit the throttle and it is immediate response, revs up all positions of the throttle, holds steady RPMs when throttle is held in place(no popping/backfiring/stuttering). When I let off throttle(fast or slow doesn't matter) it returns to a faster idle then drops to a low idle then stalls. When I try to start it back up after it stalls it takes a little bit. It cranks and then the longer you crank it it sounds like it is trying to start as your cranking but just not able to the the "pitch" it is making gets higher and starts to get faster then you can let off the starter button and it slowly catches and comes up to an idle.

    Tom

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    Just skimmed through your post, don't get frustrated you'll get it sorted. Looks like you've did a carb rebuild/cleaning and checked for restricted fuel lines, checked restricted air filter, vapor locking(fuel cap off) and intake boot leaks between carb body and engine intake port(which would actually cause hi idle lean issue) and still haven't fount your gremlin.
    My vote is for a still gummed up carb that needs a thorough clean...it doesn't take much debris at all in a passage or jet to give a guy a headache.
    Take an old saucepan and outdoor camp stove(you can do it in the house but it will give off odor)and pour in 2qts of Lemon concentrate and bring it to a slow boil. Have your carb disassembled already and drop in the body,bowl,jets and screws(don't add the float or rubber orings/gaskets) and let it set for 20-30 minutes under heat.
    Afterwards I boil straight water with the pieces in the pan for another 30 minutes to get the residue off left from the lemon boil and use compressed air to blow through passages and dry the carb.
    Just disassemble your carb down as far as you can before doing the boil(air/fuel screw etc) and I think you will have a really good chance of this curing up your issues.....I've done this quite a few times with great results.
    Oh....and if you haven't yet I'd through in a new plug as well, give yourself the best chance. Mabey the previous owner has been running rich and blubbering along for a spell.

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    So I took it over to Brother in law's (hate to do cause now I owe him house maintenance work) and we went over the wheeler. A buddy of his stopped by shortly after I got there. They are both experienced in auto mechanics (1 active the other not any more). I explained what I had and hadn't done, what the wheeler was doing and what I was ready to do with it. After 2 hours and multiple diagnostic tools they have come to the conclusion it has nothing to do with the carb or fuel system at all. They tested the engine electrical and came to the conclusion it has to be a combo of the plug wire has too much resistance and there is something wrong with the ECM and rectifier(sp?). Found the latter on ebay and they are ordered. Went to Kawa dealer to get a plug wire and ended up ordering from ebay too. My wheeler the plug wire is replaceable but the new part from the dealer the plug wire and coil are one unit.

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    Sorry I couldn't of been more help. From what you described I really thought it was a carb issue. Hopefully your ordered parts do the trick, and look on the bright side, you carb should work like a champ for quite a while now! lol
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    Quote Originally Posted by BIGAKSTUFF View Post
    Sorry I couldn't of been more help. From what you described I really thought it was a carb issue. Hopefully your ordered parts do the trick, and look on the bright side, you carb should work like a champ for quite a while now! lol

    And if it doesn't I could more than likely remove rebuild and replace blindfolded with as many times I've had it out.

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    Update: installed new coil/plug wire, ECM and rectifier. No change to runability problems. Got so frustrated I just let it sit and figured no wheeler for moose season. Brother-in-law calls me up the night befor I was going to head out for moose trip and says "I don't know why or what but it is running great right now". So I head over to his place to test it out. Started up perfect, idled perfect, drove it around for about 30 minutes and no problems. Shut it off, went and had a couple cups of coffee to let it cool off then tried it again and same thing, ran great. He said all he did was pull the covers off the valves, checked them for clearance, non needed as they were dead on center of specs. Pulled the inspection cover off timing chain and the marks were dead on. Put covers back on and started it and it was as if the problem had never been there. So I loaded it up and took it with me on my hunt, figuring if it had problems again oh well since I was planning a walk in anyway. Used it to get up the trail quicker and less work on my legs to my "off the trail starting point". 10 days and not one issue. After I had it home for a couple weeks sitting on the trailer I went out to see if it would stay running good or revert back to it's old tendencies. It fired right up and ran around on the local trails, again with no problems. All I can say is I'm confused BUT happy with it for now.

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    Sounds like the obstruction in the carb finally passed and cleared itself. Im betting the pilot jet circuit have some blockage. Pour some seafoam (available at most auto parts stores) and go run the hell out of it for a day. Glad it is finally running for you.

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    I agree with the debris in the carb as well. Glad it running well for you....

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