Hi

When I start my atv it starts and idles fine, but when I give it gas it boggs/sputters (kinda like a fould plug) and then once you have past 1/2 throttle it takes off and runs great untill you get off the throttle, when you pick it back up it boggs/sputters and then clears out. If driving slow it seems like its loading up. I checked the plug it was black. when it sputters black smoke comes out the exaust. It will do the same thing wheather its in nutral, drive or revers. I looked at the carb and there is some fuel coming out of the overflow line, not a lot but it makes the motor wet after a few minutes of running. I think it might be getting to much fuel. Its also spitting fuel into the breather box. I just bought this atv 3 weeks ago and it only has 1400km on it.

things I have done since I bought it.
-cleaned carb 2 times (it was the dirtyest I'v ever seen it was like a scum buildup in it)
-changed fuel filter 3 times
-drained fuel tank and vacumed the tank (there was dirt in it)
-cleaned the filters in the tank
-added new fuel, ran 1 1/2 tanks trough it now
-new air filter
-new oil
-changed the needle and seat
-changed plug

any thoughts as to what this could be?
thanks

did you submerge the carburetor in carburetor part cleaner over nite? or did you use a carburetor spray cleaner. there are some very minor fuel passages in a carb that controls midrange rpm exactly where your problem is at.
that scum/gooo/tar that you talked about "will not" come out with carburetor spray cleaner. it needs to be submerge overnite in the gallon carb cleaner with a basket.
and then it needs to be air out with a high pressure air hose and then i would use the carburetor spray cleaner to top it off.

I think you should read these posts. http://forums.atvconnection.co...tid/11/threadid/528212

A few day's ago someone had a post about an 01 sportsman 500 that was bogging down , a few's replys from people saying it was an exhaust cam lob going bad ; even the guy's Dealership machanic told him that the exhaust cam lob was noteable for this exaust cam lob wearing out !
And the member who made the post tried everything to find a fix , on his last post he said it was just his luck ; and that it was the exhaust cam lob was worn off the cam !

I don' know much about Polaris engine's , but i didn't think that was his problem i thought it sound like carburator or valves needing an adjustment ; but he and his
machanic concluded it was the exhaust cam lob !

But if i were you i would get a gallon size can of Berryman's chem dip , and remove the carb and give it a good cleaning ; i don't know what state you live in ( it's not sold in california ) but it's the strongest carb cleaner you can get !
You must tear the carb apart removing any rubber gaskets , and anything plastic before dunking the carb , the can has a small part's strainer basket inside to put the carb and small part's for cleaning ; it only take's a dozen or so dunking's 5 to 10 second's at a time should clean the dirtest carb you can find !

I cleaned the carb on an old 86' Honda TRX3500 4x4 that was gunked up the way you described your's , and on the first 5 second dunk you could see the gum and varnsh melting from the carb ; it only took about 5 or 6 dunking's at near to 10 second each time for my carb to be rinsing in a seprate pan with acetone to remove and dry the carb and reassembling !
And since your carb and tank being that dirty i would replace the fuel line from the tank to the carb , and install an inline fuel filter between the carb and tank and while the carb is apart check the float it could have a leak ; just shake it and listen to hear fuel in it !
The float and inlet needle sound's like it's sticking , this would account for the fuel overflow , just give the carb a good cleaning and the other directions ; and after you've cleaned everyting ( fuel tank included ) before you put gas back in tank get a can of Sea Foam to mix with your fuel !
You can get the Sea Foam at most Auto Parts Stores like Auto Zone , Advance and O'Reillys Auto Prats Stores i get mine from O'Reillys Auto Parts for $5.99 + tax it's the best fuel additive i've ever used ; Sea Foam is a fuel cleaner/stabilizer that clears your entire fuel system and also cleans carbon deposits inside the combustion chamber and has a drying agent ! One 16 oz. can will treat from 8 to 25 gallons of gas or diesel and it's safe for 2 and 4 stroke engine's , and if this doesn't work check the valves clearance and pray it's not the Exhaust cam lob that was mentioned at the start of this reply ; good luck and keep us informed ! ...........

Strange if it was to be the Exhaust cam with only 1400Km whats that? only 850 miles! Our 97 SP500 with 7000 miles still has the original cam.

Yes I used the carb spray and then air, I will try it setting in carb in cleaner overnight. Thanks alot
The night I bought it, it bogged once I thought it was running out of fuel, I turned it to resv. and it didn't do it anymore.
When I got home the next day I unloaded it and it was bogging in mid range throttle, so I cleaned and changed all those parts. Then after that it only did it sometimes so I changed the needle and seat because I saw the fuel coming out the overflow line and thought it wasn't sitting right and getting to much fuel. After changing that now it does it on take off and when gettting on and off the throttle, but on full throttle it works fine.

should I put everything in the bucket of carb cleaner or just the carb?

do you think there is anything els that could be rong?

thanks alot

Thanks alot

so if I used Yes I used Berryman's chem dip just keep diping it untill its clean and then use the air to dry it?, or can I leave the carb in over night?

take the pilot jet out and get all the holes opened up in it

I've never had to leave a carb soaking over night with the Berrymans before , i've cleaned some very gummed up part's in 30 minute or less ; you need to completely disassemble the carb and remove any rubber or plastic Gasket s and put all the carb jets and metal part's in the basket and dunk it a few times in 5 to 10 second intervals !

For tuff spot's you can use a part's brush , i use my old tooth brush to scrub hard to get to spots ; unless it's very dirty i wouldn't leave it in the chem dip over night !

You can rinse it in a pan water if you want , but i always use acetone afterwards ; acetone will dry out water fast i use it when washing out fuel tanks as well as carbs and compressed air !

Good luck with your quad , and i hope all goes well ; and that it's not like someone said about Exhaust cam lob i just don't see how one could wear out that fast ! ........