carburator problems

[devilbikerdude]

hey my webber 4 brrl carb is having some troubles, i went to start up my scout and it will start and then die after like 2 sec but if i keep giving it gas it will still run but only at about 3000 rpms but anywhere under that it will start to die, its not the fuel pump or filter cuz i changed the filter and i can see fuel going into the carb, i think it might be because the butterfly flap is not moving and it will only move if i pull the choke, iv been told by a friend that it needs to be rebuilt but i dont want to waste the money and time if it doesnt even need to be rebuit, so what do you guys think?

 

[scoutabout]

I'd say to check the regular stuff:

float level
idle mixture screws
are you sure gas is getting in?

I'd go for the rebuild if it's been a while since it's been done. It isn't expensive, and it's even cheaper if you do it yourself.

 

[devilbikerdude]

thanks, how hard is it to rebuild a carburator, if i were to mess up on a small part or something like that would it be easy to fix or would rebuiding it be a difficult task?

 

[mikeswrangler]

rebuilding is not that e-z.. but if you dissacemble it and put the parts in order they came off.. it should go back the same..

but before you do that.. go and get a carter afb and put on it.. its a better carb..

the old one sounds like its a stuck power valve.. or there is a filter on the carb where the fuel goes in.. check that one also..

 

[cowmilker]

How are the ignition components? A bad cap & rotor can make a motor run funny like that, or bad plugs, or wires. If one or two cylinders are bad then it will take all the power from the rest of the engine, thus making it not want to run at lower rpm's.
The other thing that comes to mind is the float (like scoutabout said). I have had one get a hole in it and it sunk, think about what your toilet would do if that float got a hole and filled with water, this may be why it wont run under 3000rpm, your float bowl is overflowing because the needle&seat is not shutting off the pressure from the fuel pump, and you have a condition that is too rich for the plugs to fire at lower rpm's.
Once or twice in the past I have just pulled the top of the carb off and replaced/reset the float and put the top back on (the edlebrock/carter AFB are designed to be able to pull the top off so you can change Jets/Rods/Floatsprings).
I would second the motion to put an AFB on it!
If you do decide to go get a carb kit you only have to go as far as the problem is (If you find out it is just the float, put a new on in it and put it back together)don't tear it down any farther than you have to, you will save yourself a big headache. Also most GOOD carb kits should have an exploded view of all the part and where they go!