i have a 69, with a pontiac 350.It has a holly 4160 series(1850-4) carb. It runs real rich at idle. I can see gasoline leaking out of the secondaries at idle- should it do that ? It seems to run rough until about 30 mph. About a week ago it seemed to run much smoother, now it is running rough.

I changed the plugs and wires.

Any thoughts??

the holly carb is the most likely culpret.i would get a quadrojet at auto zone and i bet you will have no more trouble

Check the float level first.

I'm not real up on my hollys, but if there is fuel dumping in the secondaries, there is a problem. someone else may know what it is. I'll try to find what controls the circuit on that. The secondaries normally open by vacuum on them, and a different spring can keep them closed longer, i think, but don't think that would dump fuel at idle (?) are the secondaries hanging open at idle?

Sounds like you need to adjust the rear float. I had the same problem a year or so ago.....

After you check the float levels play with the idle mixture screws. Also check for vacume leaks. If the carb is old the shafts may be worn and leaking air.

thanks guys i adjusted the rear float and it runs fine now!

Glad to hear it worked out for ya.

Drew

sadly i took the car out for a test drive and my thought was wrong. The good news is the car is no longer running rough. But it was stalling, about 3-4 times in stop and go traffic. I hiked up the idle speed and played with the float levels for a whole afternoon.

To add to my troubles the powerbrakes were no longer functioning for some reason. I had to put my foot all the way to the floor on the brake to stop. I'm guessing this is a vaccum leak? That I could not find lol!

My next idea is to just ditch this Holley and find a simple 2bbl carb. what do you guys think?

Pavell,

Depending on your mechanical inclination, you can learn how to diagnose & fix what you've got, or be doomed to buying parts until eternity comes to fix things.

You have hit on something with power brake problem. You obviously have a vacuum leak somewhere. This will really screw up the way any engine runs with any kind of carb. What kind of intake do you have that Holley sitting on? It maybe be leaking between the intake and carb. Find that leak! As a tip, Holley's have power valves which are notorious for causing problems when they get old or have the wrong vacuum level installed which causes real bad driveability.

Here is quicky article on a Holley 1850 rebuild.
web page

Found this also,
web page Holley Instructions

Pavell, when you were adjusting the rear float did you disconnect any vacuum lines? Check the big one that connects to the power booster first, then check the smaller lines.

no didn't disconnect any vaccum lines.

but i took it to a show it stalled on the way there.

on the way back it ran great, finicky holley hehe

ill take another look at it tommorow

Did you lift the carb off the intake? You may have a leak at the base gasket.

Holleys are no more or less temperamental than any other carb.

BTW, did you get your steering column issue resolved?

Thanks for all the feedback guys/girls. I would never have been able to come up with this stuff myself, and GTOken that was an excellent piece of advice!

The steering column issue has been put to the back burner now lol. I haven't got around to fixing that yet.