hello i have the previous 09 bmx 300cc idling slash starting/all out carb problem. well if i could get some more help here fellas we would be helping a lot of people who probally have this problem. well just because i have not been posting in the last week or so on here i have been diligently trying different things and just searching for information on this for hours. okay my machine starts hard as hell i have turned out the idle/air jet to 3 turns from 0 it was set at 1 3/4. this is a brand new carb okay i have been reading just several instances of conflicting reports. this is what i found tonight when the motor is rolling over this electric choke or enriching valve whatever you want to call it is gettin about 4 to 5 volts dc and cold the needle is fully retracted. when the machine finally starts it is getting about 10 volts and as the rpms are brought up this voltage raised on my machine to as much as 17 volts dc at this point this device starts heating up and the needle extends out at least a full half inch. okay i took my old one apart it is junk and stays in the full retracted position all the time with 12 volts dc applied. so now i no the new carb choke/enriching valve is operating. so now the machine still dont idle till i adjust the idle screw to make it idle and as it warms up the motor starts revving so now with a warm engine i adjust the idle again till its as low as i can take it without stalling. now at this point i removed the choke/ enriching valve from the machine and the idle smoothed out very nice and just continued for several minutes then i stuck the valve back it and bam machine runs like crap and ruff idle again. this is were iam at this point. so now iam going to wait till tomorrow night and i put the bad unit in that wont extend and iam going to see if it will start easier. this is were iam at. so as i go through this five minute starting process iam hoping that the machine will start easier with the broke valve that is in the retracted position. so iam thinking in this position the carb should be seeing more fuel in the starting phase. also i took the slide out of the old carb it has a needle in it with just a spring on top and is operated by vacumne. i dont know how this works but obviously it has the long needle that goes into the main jet in the float bowl. am i right does anyone no. because as you open the throttle on this carb i dont see the slide move only the butterfly valve. and also everytime that throttle is actuated you can see the accelerator pump shoot a stream of gas at that slide. that is another thing that baffles me. if that did not shoot fuel at the closed slide it would actually shoot gas into the intake and maybe it would start easier. just like a primer. i would like to add one of them and drill a hole in the manifold for it to help this thing start easier. i have not yet shot gas into the carb to see it it would take right off. i will try that soon to. a few days ago i went out 1st start of the day pumped the thing about 10 times and it started right off quick. tried it later in the day and i flooded it and could not start it for 10 minutes. another thing it has a steadly yellow spark at the plug i see. this may mean nothing. dont know at this point.

thanks
jim

 

well i figured out a fix for this problem. the fuel enricher valve or choke takes 4 minutes to shut off. so while starting i let the fuel pump run about 30 seconds pump the machine 2 or 3 times take the key back to mid position so the fuel pump is still running you do this maybe 3 times and the machine starts much easier. now the idling problem there is a small line running form the intake manifold to what the parts breakdown call a one way valve. this one way valve is also piped down to the exhaust pipe. this valve also has another hose that goes to what i see as a white charcoal canister and from that canister out eithier to the airbox or just into the atmostphere. well my machine does not have a hose on the other end of the canister. if i unplug the small hose running from the intake of the carb to the one way valve the machine idles and runs perfect. so it it my belief that the one way valve and or canister is bad. now iam comtemplating putting a small airfilter at the end of the hose coming from the manifold or iam going to run a hose all the way to the airbox so it can draw in filtered air. this is a win win for me on this machine. it has been such a absolute nightmare. now its amazing. iam not buying a new one way valve for it but i may get a new hose for the charcoal filter after i find out for sure were it goes to the airbox or another device or just out to the atmsophere. eithier way now it is fully functional and runs great and i can keep pushing forward on it. the whole problem with this machine was that the previous owner kept pulling parts from it and scabbing things together to keep it running. so you live and you learn.
i did not get much if any help from this forum other then from my wifes quad but thankyou all.

jim

 

i apologize. i did not see this post soon enough. please don't get discouraged with us.