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79 camaro with new carb

i just got a new carb for my 79 camaro (305 v8) its a 2 bbl dueljet Rochester. we have been having problems trying the get the mixture right. When it turns over it sounds really good and sounds like it wants to start but just wont. Can someone help?

Was the carb used when you got it? Was it rebuilt? Why did you put a 2-bbl on the engine when it likely came with a 4-bbl? Did the car run before carb replacement? If the carburetor has a fuel filter just past the inlet (where the fuel line screws in), has this been checked/replaced? Has the float level been checked? Do you smell gasoline when you crank the engine? Are all the vacuum lines hooked up correctly and any unused vacuum ports plugged?

Turn the mixture screws 2 1/2 turns out. Start the engine and turn one mixture screw in until the engine begins to stumble then turn it back out until the engine smooths out. Repeat on the other mixture screw.


My 79 Camaro had same motor/carb. Look down throat. Push throttle linkage. Can you see gas squirt down throat? I took off intake, saved carb, tossed intake and put on factory 4bbl and drove for several yrs. than I decided to go back to stck. Went to junkyard and found identical car but carb was missing. Every other part/hose was there. Talk about good luck.

I bought the carb new. And I also looked to see if it was getting gas , and it was squirting gas into it.

here’s carb

I can’t comment on your specific carb, but I have experience with a Motocraft 2150 2 bbl., might help anyway.

If you spray starter fluid into the air intake, does it start then? Or you pour a small amount of gas right into the throat of the carb? (When I do this, I always only attempt to start the car with the air cleaner fully in place to avoid the undesirable effects of an engine backfire through the carb.) When you add extra gas in either of these ways, does it start, run a few seconds, then stop? If so, not enough gas is being metered by the carb for a given amount of air flow. If adding gas this way makes it worse instead, then the carb is metering out too much gas. Either way, something is amiss.

The amount of gas a carb meters out is built into the geometry of the carb, but is tweaked to optimum by the jet size, the intake manifold vacuum, and the fuel height in the bowl. Something among those things appears to be not quite right. Have you measured the fuel height? Have you measured the intake manifold vacuum? Those are two places to start. And verifying the jets aren’t clogged would be third on the list.

Are you certain it’s a carb problem?? Engines will start and run with very poorly adjusted carburetors. They don’t run very well, but they will run…If yours will not even start and run for a few seconds at least, then it might be time to look elsewhere…If you have the equipment to check the timing with a strobe light, do that at cranking speed. If you can’t even see the timing mark and your set-up is correct, then chances are the timing chain has slipped and the engine is out of time…

Is that a new distributor cap, rotor, wires, and so on? If so, any chance the wires, or some of them, are not in the correct order?

From the pic looks like a pretty straight car. Those Camaros are hard to find around here as most of them were bought up and converted to dirt track race cars; usually followed by wiping them out in rollovers. The north end of the track has no retaining wall and it’s quite a ways down and across the field… :slight_smile:

Kind of a shame.

How many miles are on the car? The engine may have jumped time.

How did the engine run before the new carb?

U changed carb to fix something? Was it running good/ bad before u changed carb? Probably bad since u changed carb. But maybe funky carb was compounding other issues with car?

I brought this new carb cause it really need a new one. And im pretty sure its not a carb problem anymore cause it is getting gas and it did start up twice but only for a few seconds. so i know the carb works. The camaro has 176K miles on it. And also that is the old distributor, but cap and rotor are new.

Before you started all this work, was the car running? Is that some kind of silicone sealant I see around the base?

Before any of this it ran but it would sometimes have a hard time starting and it didn’t really sound to good. The only reason we brought it in , was because we had to replace the head gaskets .

Does this mean that since replacing the head gaskets you have been unable to start the engine?

If you have not started this engine since replacing the head gaskets, I would look at those rocker arms, you may have them too tight and the valves are not closing completely. You can do this with this engine.

Fuel pump on the fritz or clogged fuel filter could cause this symptom. As well as a dozen other things. If this were my car I’d revert the configuration back to a condition that it ran like before, then change things one at a time. Should be able then to diagnose what component here is failing.

well like i said before it started twice before but now it wont start again

Well, u did replace headgaskets which is a complicated job but that means u r fairly handy. You adjusted rocker arms, set distributor timing, routed plug wires, and so on.