Only starts with dropping gas into carb.

Discussion in 'Whizzer Motorized Bicycles' started by Sangiovese, Jul 5, 2011.

  1. Sangiovese

    Sangiovese New Member

    My problem seems to be a bit of several of the threads I've been reading. I have a 1999 Whizzer - has been sitting for a couple years in storage - used to run easily. Now it won't turn over. New spark plug, fresh gas, choke in proper starting position, fresh battery. But when I put some gas directly into the carb it starts right up and then stops. I think it is getting gas because gas pours out of the hose attached to the bottom of the carb. Is it a stuck float? Should I take the carb apart and simply give it a good cleaning since it used to start easily? One clue might be that throttle was really stuck at first. I got it loose with some carb cleaner. Any help would be appreciated. BTW trying to find a repair person here in Seattle if anyone knows of someone.
    Last edited by a moderator: Dec 15, 2015

  2. motorpsycho

    motorpsycho Active Member

    yep, sounds like the float is stuck.
    gas may be flowing out of the tank, but if the float is stuck in the up position, no gas will get into the float bowl.
    if old gas was left in it, it will gum up the inside of the carb.
    take the carb apart and clean everything with carb cleaner.
    you may even have to soak the carb in a can of carb cleaner to get the gum off.
    some carbs have very tiny hidden passages, and they may be plugged up with gum as well. you may have to get some wire and run it through any small holes that you see to make sure they are clear.
  3. Sangiovese

    Sangiovese New Member

    Thanks very much! I've never taken a carb apart but your tips made it clear. I did all of that. It was totally gummed up in bottom of blow just like you said. Cleaned it all up with carb cleaner and watched it shoot out the holes to be sure it was open. But still won't start unless I put gas into the carb. Could it be the trottle? But then there is definetly gas in the bowl. Everything is the same settings as when it started before. Air and gas screws are set about 1 turn off of closed. Any more good tip would be appreciated.
  4. motorpsycho

    motorpsycho Active Member

    did you make sure that the main jet is free of gum?
    the main jet is how gas gets from the carb into the engine.
    the throttle should have a cylindrical slide hooked to the cable with a long needle attached to it.
    when you give it throttle, the slide raises up allowing air to be sucked into the carb. the long needle also raises up at the same time, allowing gas to be sucked up through the main jet, into the incoming air stream. the gas atomizes with the fuel and enters the engine.
    make sure that the throttle works smoothly and that the slide moves up & down lowering and raising the lomg needle.
    I'm not sure on the air/fuel ratio screw but you may want to screw it in until it stops, and back it out like 3-4 turns. i turn out may not be allowing it to get enough gas.
    as long as it will run when you drip gas into the carb, that's a good sign (meaning that you have compression, spark and air).
    now you just have to get the carb working right and it may just be a matter of tinkering with the air-fuel screw.
    make sure that the idle screw is set to allow the engine to idle (you can set that once it runs on it's own, but screw it in to raise the idle a little bit.
    make sure that the choke isn't stuck closed (not sure what kind of choke it has) and that it moves free. if the choke is stuck open, that's ok, but it may be hard to start.
    you can cover the end of the carb with your hand while trying to start it to simulate a choke if you need to.
    i think the problem may be that the main jet is plugged up, or the air-fuel screw is set too lean.
  5. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Your low speed system is stopped up. Remove both main & pilot jets, air mixture screw, remove float & needle , soak carburetor in cleaner [I would suggest gasoline, however not politically correct]. Let soak over night and then use an air hose to blow into passages [never use air if the float bowl is attached, as it will crush float].

    You may need to repeat this process several times. You CAN'T remove and residue with a wire as the passages are way to small.

    You problem is common, as todays gasoline will evaporate quickly and leave a terrible residue behind. I put several ounces of Gummout carburetor cleaner in about every 5th tank of gas [I ignore the instruction of one bottle per 20 gallons], and avoided always cleaning carburetors.

    Have fun,