Carb Help

Hey, well I am new to the forums.
Alright, so being 16, I have picked up my 1st car. 1977 Monte Carlo. Just having lots of fun with it, slammed it, sterio, etc.
So now the problem. When I bought it, it ran like a dog, so I bought a new carb kit for my stock carb. Engine is a 305 chev. Carb is a stock 2bbl. After rebuilding it, and setting everything, the car ran mint, hauled real good as well. But a few days ago, after pulling the car out of the garage, it seemed to run reaaal boggy, only when it was at idel, and I would hammer the gas. And would sometimes stall. I re-adjusted the mixture screws, but still nothing. It seems like the carb is shooting too much fuel, because I can see lots of extra and some even spraying up out of the carb. And when it bogs, most of the time fire will also shoot up.
How can it go from being fine one day, to totally crap the next ?
I am totalllly stumped. Any help ?
I know it can't be timing, because I didn't touch it at all. Its only when it idels, and you punch it, its real bog. But in the higher Rpms, its fine.

Sounds like the "choke" adjustment.

when you rebuilt the carb did you replace the float?

Choke is off. I am even doing this with the air filter ass. off.
Yes floats were replaced. And spaced to specs.
Just all of a sudden runs like a dog.

its real hard to tell with out seeing it. But is the carb overflowing & flooding? If so it sounds like a piece of trash has gotten stuck in the needel & seat & not letting it close. therefore too much gas is pooring in while idling & its flooding. Sometimes beating it with a hammer (gently) will dislodge it but likely you'll have to disasemble it again to clean it.

Alright, well I fiddled around with the mixture screws and choke, to where now at IDEL, it rums real good. Now, only when driving, it gets boggy, and fire comes out the carb once again.

Sometimes trash will get in the idle ports as well & will cause it to idle bad but will accelerate ok. Remove the adjusters & try to clear the ports with compressed air, then thread them all the way in till they bottom out, them back them out 2 1/2 to 3 turns, it should idle good that way. As far as it back firing--- you should check your timming. Those early 305s were famious for the timming chains jumping & the cam shafts flattening. How many miles are on it?

Alright thanks, that was my next bet, to clean out the carb again, and check timing.
For miles, I really have no clue. The car is pritty rough, and the spedo reads 99,000. It is only the 5 digit ones, so it could have rolled over a few times.
When I had the engine running mint, it was real tight and responsive so I don't see anything wrong there. All fluids were replaced, valves spaced to specs.
Now, how can I go about checking timing on this older engine ?
I will try tomorrow, and keep updated.
Thanks.

the same way u check a newer engine-with a timing light. remove & plug the vacuum line on the distributor for the vacuum advance (bell-shaped, on the bottom of the distributor, right side). connect the timing light 2 the battery (for power), and the spark plug lead to plug wire #1 *check to see if there is an arrow on the clamp for direction*. the timing for your engine should be 4 deg. u can play with this a little to get the best performance out of it. keep in mind u have a 2 bbl. carb, and the age (mileage) of your engine.

Did it ever backfire on you just before it started flooding/bogging. If it has and the carburetor is a Holley it may be the power valve is blown. I wouldn't mess with the timing if it ran well before. Also, if has been flooding quite a bit, you may want to check your oil level and ensure it hasn't been contaminated with fuel. If your suddenly half-a-quart HIGH, your oil is useless.

First problem is that it is a 305. Unless you do some mods it will never be a powerhouse. The next issue is that it is a stock carb. You need a Holley. No need to worry about a power valve blowout Holley fixed that problem years ago. Get you a 600 CFM with vacuum secondaries. The Holley site gives you all the info you may need.