leaking gas out of the top tube by the air mixture screw after I removed my carb on an '02 400 Big Bear 4X4 as it was leaking gas out of the bottom drain/overflow tube; so figured it was a stuck float and did not know what else to do (already sprayed and ran gumout through carb). The float seemed stuck when I took the bowl off.. I moved the float up and down and it seemed ok.. so when I put the carb back on the quad it now runs like it is cold with the choke on (alomost sputters) and leaks gas out of the top tube (not sure what the name of the tube is but essentially it just goes out to the atmosphere). If I turn the gas petcock off it runs great for about 15 seconds until it runs out of the gas in the carb.

Any help would be greatly appreciated... thanks.

 

the floats are probably sticking. my 99 did the same thing after the dealer rebuilt the carb. it was intermittent, but it was still a huge pain in the ***. if i were you, i would see if holley or edlebrock makes a replacement carb. those mikuni carbs yamaha used were nothing but pure crap in my opinion.

 

Thanks very much. Do you have a link to a supplier of holley or idlebrock..o/w I will search the net. I have been using the quad for utility work and can't afford the down time.

Thanks again,

--Greg

 

Pull the float bowl off again and clean the float needle and seat really well with carb cleaner. Also hit all the jets and passages with cleaner and compressed air.
Any spec of dirt on the float needle or seat could keep the float open enough to flood the carb.

The Mikuni carbs are not junk. And only reason to spend $400 + on an eldebrock would be for racing applications IMO. Mikuni has been making OEM and aftermarket carbs for years.
A good cleaning is needed for any carb every once in a while. The gas most people are running now days can cause havok on any rubber parts inside the fuel system. Or just gum up if not used often.

 

the reason i say they are junk is there are far too many ATvs having problems with these carbs. prejudice? maybe, but there are just too many problems with the design i guess. look at it it this way, if you have a hotrod, and you replace the carb, do you go with oem or a good edlebrock or holley?

id dump the cash in a better brand. i know that denniskirk.com used to have a lot of carb applications, and some were aftermarket.

 

Personally I have a hotrod and I prefer older carbed vehicles and work on all sorts. If I replaced a carb it would definatly not be a Holley. That is pure racing and not much good anywhere else. Eldebrock is decent and easy to get parts for but is just a knock off of Carter units which are OEM for most older vehicles.
I build and work on my own so I would stick with OEM since parts are abundant, cheap and if tuned right will beat most aftermarket set-ups in performance and fuel economy.


I think the main reason you see most having problems with these carbs and any other atv carb are from type of use. They do not get used everyday and get neglected. Gas will sit in the carb for sometimes years. Newer gas is hell on rubber parts. And I believe it leaves alot more gunk once it's evaporated. Once the fresh gas hits it, you end up with a nasty mess inside the carb. No fuel filter inline and a little dirt in the tank will cause havok also. And it doesn't take much dirt.