i want to shoot this out there and hopefully i can get some answers. i posted on this site a month ago about my machine having idle problems. well i put a brand new oem carb on it last weekend and it still has a irratic idle. you can adjust the idle to were it seems good then it will change. how does this electric choke or electronic idle control work on this machine. am i missing something what actually controls the idle. it seems you have to constantly adjust this idle to different temperatures of the motor.

jim

 

All carbs from China are jetted lean..The same as any thing from Japan that gets a green sticker in Ca..Its so it will pass emissions tests.. those folks dont care how your machine runs.. Lean jetting causes a erratic idle.. Bigger jets will help a lot.. a larger pilot will eliminate the cough and die syndrome a lot have during warm up..

You may have a vacuum leak.. (which causes a lean condition) you can check for a leak by spraying carb cleaner around the carb/manifold while the engine is running.. any change of the idle speed while spraying and youve got a leak..

 

hey thanks i will check for a vacume leak . do you know anything about the main jet where i could even find one bigger for this carb. i have not had any luck getting information on this machine. i found a site that i can get replacement parts for the machine with a actual microfich breakdown but it only covers complete items like the whole carb airbox etc . the yamaha dealer could not match up a idle air jet for the old carb so i had to buy a new one. as far as running lean i will pull the plug and look at that. the only adjustment i can make on this carb is the idle air jet and the idle screw. at least that is what i think that jet is. they had it set at 1 3/4 turns out . i brought it out another 1/4 and it does run better and will idle but you will here it idle low then pick up a little and just keep doing that. my big problem with this whoe issue is that when you have it adjusted mechanically so it will idle with the screw and your riding it you will come down a hill and take your foot of the gas and the motor still act like its under acceleration then several seconds later it will act like it should when your foot is off the gas. the motor should decel immediatly when the throttle is closed. do you know what i mean. the vacume think makes sense i hope this is what it is. i will shoot eithier at it. if it revs it would act like a leaking crankseal on a snomobile.
thanks very much. this is driving me nuts iam on the edge of do i get rid of it or not.

jim

 

well why the engine was running i sprayed starting fluid all around the carb slash manifold there was no change in engine rpm. iam going to put a new fuel filter on the machine also to rule that out. the machine is very hard starting also. the electric fuel pump may only click once or twice meaning the pressure is built up i dont know if its enough or not. it takes about five minutes of rolling this thing over and pumping gas to it for it to finally start. does anyone know what the fuel pressure should be from the pump. i can pull the line off and it is pumping fuel. i need to see if the plug is getting wet at all during this start process. i wish this just had a plain carb on it. if its not getting fuel i need to possibly think about adding a primer to it. does anyone know how the choke works on this machine. am i the only one with a chinese utv that starts harder then hell. helpppppppppppppppppppppppppp

jim

 

Turn the screw to 3 turns out and see if that helps (its sort of like getting a bigger pilot jet). If it does help then we need to figure out what jets your carb uses.. or if you know someone with a number set of drills.. 1-60 ans 61-80.. you can drill them out to a bigger size..

Im about 90% sure that richer jetting will help your utv run better.. I havnt seen a stock Chinese or Honda 4 stroke that didnt need richer jets..

Any way you could hook up a extra tank that gravity feeds to test your fuel delivery theory?

 

iam open to any suggestions to get this starting and idling issue put to bed. i also have the old carb i can pull it apart and take the main out and check the local yami shop to see if i can get a bigger one or like you said i would try drilling it out. i dug for information on this carb for 2 hours last night. it is virtually impossible i am very knowledgable of motors and have never not been able to find the answers to a problem. i was searching hard for a mikuni carb to replace this one. this carb has a electronic choke and all i could find for info was that i should be able to put 12vdc aross the 2 pins for the choke and see it function. to me this dont help much because i dont know where the machine or what part is controlling the voltage to che choke. also it is vacume assisted and its pretty technical stuff that is over my head. i can rebuild carbs and all but this new bells and whistle carb with no name is beyond my conventional wisdom. you know what i mean so just give me a old mikuni with a choke or primer setup. but i will keep on digging and really appreciat your helping me mywifes quad. hey another little thing sometimes this machine pops out of high range when you come down hills any knowledge of that. me i put most of that to a suspension that is so heavy that when the machine is empty/ one rider the rear bounces so much that being cable operated and such a close shift pattern the gearbox just wont stay engaged. i have read that it has some kind of holding mechanism to keep it in gear. iam going to try and adjust the cables to see if it is engaging fully in gear. it does not do it much but has a few times and the cables are adjustable several places. my main deal is the carb now if i get that resolved this will be a very nice machine. iam putting a new plow on it that i already bought and i also have new tire chains i just bought. i wish there was a way to put diff lock on this machine. iam going to put a lot of weight in the box so i can plow hope it works out. what do you think
jim