Carburetor Running Dry Overnight

[shortman1166]

Once my scooter is started and running it runs great, but when it sits for a few hours or overnight it has to crank for about 10 seconds before it starts up... It seems like the carb is running dry and has to suck more gas from the tank then it finally starts and runs.  Where does the gas go? I do not see any leaks. Is there a way to fix this so the carb stays at the correct level and will just start right up without having to suck more gas to fill itself back up and start?

[humanshield]

While it may seem this way, that's not necessarily what's going on. It could be a number of things.
Your motor will naturally start easier after a warm up because a cold engine requires more fuel to run than a hot one since the hot metal helps vaporize the fuel.

Perhaps your enrichment system isn't working properly? Do you know how to test it?

[shortman1166]

Yes, and it is working properly. Also once I do get it cold started I can shut it off right away and it will fire right back up even after a few min or so when the motor is still cold.

[tocoo]

if you have vacuum petcock, beforehand, you can suck on the vacuum line to get the fuel in the carburetor. You can also kick a few times before you turn the KEY ON, and leave the kick where you feel the most resistance. then you turn the key On, you either start with the kick+throttle open or the battery.

On my scooter, the same situation occurred, it was because the enricher blocked the enriching circuit even when the enricher was cold.

you can also check that your mixture screw is between 1,5 turn and 3 turns from the screwed position. ANd you can check the size fo the idle jet.

[GrumpyUnk]

As considered, the fuel has 3 places to go after leaving the petcock, and going through the carburetor fuel inlet. The floor, the float bowl, or the crankcase.
The floor if the drain is not secured or the float bowl gasket is impaired.
The float bowl if all things are good.
The crankcase(or floor) if the float valve does not work.
If the petcock is failed, you may get fuel flowing out the air horn, back through the air tube, and into the air cleaner. It will slowly drip out onto the floor at the rearmost or lowermost point of the assembly. The foam filter element will absorb fuel like a sponge until it can't.
The fuel will not likely get to the crankcase unless the fuel can go uphill in the carburetor(such as when facing down hill), into the intake, past the intake valve, filling the cylinder, and slowly seeping around the ring end gap(s) into the crankcase. It will take some time, and the oil level will be too high and/or the oil will smell like gasoline.
If the drain is not secured, you'd have a puddle or drops of fuel on the ground underneath after parking for a while. If on asphalt/tarmac(?), you would start to dissolve the floor material fuel being a solvent for the adhesive holding the aggregate in place. Like an oil drip spot, except worse.
Fuel could be in the float bowl, but not being drawn into the carburetor if the jets are plugged, or the idle mix screw set too lean. The enrichment mechanism opens and closes a 'direct' port to the float bowl as needed, or as the mix inside heats/cools. When heated the probe extends and plugs the port. When cooled, the probe contracts, and opens the port to allow more fuel to be drawn into the engind. If the port it plugged or the probe somewhat reluctant, you can obvserve hard starting, no starting, or rough running as the engine gets warmed up. A faster than normal idle speed should be obtained after starting a cold engine. The rpms should drop to 'normal' after a few minutes, perhaps less, as the probe starts to cut off flow from the enrichment circuit.
tom

 ADD: To know if you do/don't have an empty float bowl, you can open the drain on the end of the drain hose, or open the valve at the bottom of the float bowl.  You will need a longish flat blade screwdriver to reach the valve stem.  The 'armored' fuel drain lines have a valve at the end which can be opened to drain the float bowl more readily.  Either should flow fuel if opened and there is fuel in the float bowl.  Last alternative is to remove the carb and flip it over or invert it in place, either of which should dribble fuel if there was fuel in the float bowl.
tom

[greginisn]

I would be tempted to check that the float bowl was actually empty . No gas puddle on the floor? Dd you check the crank case oil level for over full and give it a good sniff for gas? Fuel shouldn't evaporate from the float bowl over night. This seems a weird problem at this point.

Greg

[humanshield]

Carbs are dirt cheap. You could just get a whole new carb and see if that solves the issue.
If not, you have a nice spare.