MOPED ARMY

gas doesnt really spill out.

How is your compression dude?

actually im pretty sure the vaccume of the motor is the only thing that draws the gas out, you can do the starting fluid test to see if its fuel or spark(timing) a small squirt should get a quick firing of the engine if all is well electrically

r u using the choke to start it???? u might have either a massive air leak or a head leak

also there is no "pump" or forced fuel injection, it works purely off the low pressure created in the intake by the piston moving up and down to draw fuel out of the jets

carbs are venturi systems... come on josh i thought u where a car mechanic thats carbs 101

Test for spark and compression. Put your thumb over the sparkplug hole and have someone crank it over. if your thumb is pushed off, you have decent compression. With that said and done, pour a little gas into the spark plug hole, turn it over like you're gonna start it w/o the spark plug a couple times, then put the plug in and turn it over. It should fire up. If not, I would check the timing. If both those tests pass, then clean the carb again.

And to answer your question, no there shouldn't be gas coming out unless the engine sucks it out.

i dont understand how the dellorto choke works. can someone explain?

clogged pipe.

bad timing

two things that usually cause back firing.

YUP! loose head nuts. time for some lock nuts.

RIIIIIIING-ING-ING-ING-ING-ING-ING

OK.... cnay let this go any farther...lol

First... A car has fuel pressure to the carb and the float/needle and seat allow the gas into the float bowl. There is no fuel pressure after the needle and seat in the carb! All automobile carbs have a "accelerator pump" that pumps a small amount of gas when you open the throttle.

Second fuel is not really sucked into the engine by engine vacuume. If that was the case how does a turboed engine with a "blow through carb work? Thats were the boost is pushed through the carb and into the engine... so there is no engine vacuume during boost... yet is still runs? Yes this was a popular way to turbo engine in the past but not seen much anymore.

Fuel actually enters the air stream because of the "Venturi effect" in the carb. The venturi is just a necked down area of the carb either cast in or made by the slide. As air moves through the carb it has to speed up to get through the smaller area causeing the molecules to spread out (less moecules in a area= less pressure or a vacume) the fuel nozzel is placed in the venturi and the atmospheric pressure actually pushes the fuel into the low pressure area.

Another way is to have your discharge nozzel stick into the bore with the engine side of the nozzel cut away... as the air goes over and around the nozzel a low pressure area is created behind the nozzel and again fuel enter the low pressure area.

Thus a pressured carb (turbo) has the float bowl pressurized and the ventury makes a lower pressure area than the foat bowl and the fuel enters the carb.

i havent seen that kind of turbo since the old volvos and such. as for the accelerator pump, that wasnt something that came around until the early 70s, and is totally standard on any after market carb now, ie holly edelbrock. older style like from the sixties still relied on fuel pressure, if you lost it you had to crank the motor a little.

how old are you ottoman? i like your knowledge of vintage fuel systems, as thats been my real passion for a decade. you wrench classics too?

nah...

mine was already off, and its not like i beaned it at him or aimed for a head shot or anything, just a "get the fuck out of here" kind a lob. i aint tryin to hurt nobody, but dude did pick the wrong time to kick me when im down.

it doesnt matter, this is a carb thread.

my car carb experience only goes as far back as mid sixties models and all domestic. and at college the main focus was on current technology, ie fuel injection. carbs were covered in my power and performance classes.

for a minute i did. now im cutting new gaskets. we'll see tomorrow