1986350

Hey guys first off i dont have a big background in carbs, but the more i read the more i think i know lol. But if any of you guys watch the news its getting bizzarelly cold in North Carolina and my car DOES NOT LIKE THE COLD. Its a 305 4bbl rochester carb

When i start my car up it idles very rough at 300-400 RPM. My dad taught me an old trick on sticking a screwdriver between the carb blade and the carb body.

So i talked to a customer at my job and he says well it sounds like the fast idle cam so he told me to get a new carb but i dont know where to get one wether its from advance auto or online. PLEASE ANY HELP WOULD BE GREAT

five7kid

iTrader: (14)

For the sake of completeness, do you give the throttle a tap before you start the car cold? If you don't the fast idle cam won't be set properly.

Second, do you know if your choke butterfly is closing? The easiest way to check that is to remove the air cleaner when the car is cold, and just look at the butterfly. Open the throttle a little, and the butterfly should snap closed. If it doesn't, either a) the choke thermostat is bad, or b) there is something wrong with the linkage - bent, binding, gummed up, or missing. If gummed up, a rebuild with a thorough cleaning usually takes care of it.

Oh, when you open the throttle a little, a green weight on the passenger side of the carb should flip up - that's the fast idle cam.

With the choke butterfly closed, when you start the engine, a vacuum "pull-off" should engage and open the butterfly slightly so the engine doesn't over-choke. You don't want the choke to open completely right away, but to open gradually as the engine warms up.

Make sure there is an electrical wire connected to the choke thermostat (the round black plastic thing on the passenger side of the carb). If it isn't hooked up, I'd suspect someone in the past has disabled the choke.

If everything appears to be working properly, then perhaps the fast idle speed simply needs to be adjusted.

You can get a rebuilt carb at most any parts store. I've seen what look like good rebuilt carbs on eBay, but I've never purchased one or know anyone who has.

1986350

thanks five7 i was hopeing you would see this and yes i do press the gas about 6-10 times and yes when i look at the choke blad in the morning its closed and then after 20 min of the screwdriver trick the choke blad sttays open. my buddy that thinks hes a mechanic says it the choke pull off but like i said i dont know ok five7 yes the electric choke is plugged in but the light doesnt come on in the car for about 20min.

Air_Adam

Sounds like the fast idle needs to be adjusted. A pic is worth a thousand words, but I dont have one. Its a tiny little screw between the choke thermostat and the carb body, near the bottom of the carb. Raise the fast idle to about 1400-1600 cold and you should be good.

1986350

hey guys *update* i found a blue terminal on the top passenger side of the carb this morning, i plugged it in and did my screwdriver in the choke and when i would go to push the gas down it would suck in a bunch of air and then die.

I ended unplugging the cable and it went back to normal. so with it plugged in i cant acceralte with it unplugged i can accerlate....if that makes sense.