1978 trans am flooding out

Its a 78 trans-am with the pontiac 400 v8, with the 350 heads. (220 horse motor). It will run fine for a while, then when you pull up to a light and idle for any longer than 30 secounds it starts loading up then floods out. I rebuilt the carb last year, and it ran great for a couple months then it started doing this crap. I know it got a little grit in it the first time it started doing it, so i replaced the fuel filter. But it seems like every other time i run the car it does this. Any ideas what the problem could be?

is it a quadrajet? ether way it sounds like the needle valve is leaking did you replace it when you did the rebuild

If you're still using the stock mechanical fuel pump, I'm thinking the float in the carb has gone "heavy". The fibre (nitrile, I think) floats are known to act like a "sponge" if they sit inactive for any length of time. We use brass replacement floats. Any time you open a Q-Jet, if the float isn't brass, replace it, and if possible, replace it WITH a brass one.

FWIW

Jim

I replaced the float when i rebuilt it with a brass one, and i did replace the needle valve.

A freind said there might be dirt getting into it from the gas tank, is that possible.

its possible if you don't have a good filter on it
also if the lines going to it are in bad shape you could get some contamination from them as well

Jason is correct. The filter is housed inside the front of the carb, behind the fuel line. First remove the flare nut (hold the BIG nut, 1", and turn the small one WITH A 5/8 "LINE WRENCH", not an ordinary open-end, as that can and will "round" the nut). Next, remove the big "nut", as that is the filter "housing". There's a spring in there along with the little filter. The spring should be behind the filter. Make sure to re-install it that way. A new filter is less than $5 at most parts stores. If it hasn't been replaced since the carb rebuild, it won't hurt to replace it, even if it doesn't solve the problem.

A clogged filter won't cause the flooding issue, but a torn one, along with debris, or worse, a MISSING one, CAN cause the problem.

Jim

Jason is correct. The filter is housed inside the front of the carb, behind the fuel line. First remove the flare nut (hold the BIG nut, 1", and turn the small one WITH A 5/8 "LINE WRENCH", not an ordinary open-end, as that can and will "round" the nut). Next, remove the big "nut", as that is the filter "housing". There's a spring in there along with the little filter. The spring should be behind the filter. Make sure to re-install it that way. A new filter is less than $5 at most parts stores. If it hasn't been replaced since the carb rebuild, it won't hurt to replace it, even if it doesn't solve the problem.

A clogged filter won't cause the flooding issue, but a torn one, along with debris, or worse, a MISSING one, CAN cause the problem.

Jim

thanks Jim, normally what you say works. I have the car in the garage this weekend and plan on taking the carb off today and checking that. I'll let you know.

well i cleaned out the carb, there was a little bit of gunk in it. little black chunks, they kinda looked like rat turds.i cleared those out. cleaned the jets out, then reassembled the carb. The filter appeared to be in good shape, so i am not sure how the junk got into the carb. Then i tried to run it, it was surging and idling poorly. then once it warmed up, it just wouldn't idle at all.

I heard ticking, could it be the cat is clogged?

My dad said it might be the distributor