I'm new to this site, but if I can get help anywhere it's probably here. I have a 73 dart swinger thats a daily driver.
I just got the thing a week ago, so far i have done a tune up, 2 oil changes (one was a flush), I changed the coil with the tune up, i rebuilt the 1920 carb, and adjusted the valves.
The problem I'm having is that at high engine load, at lets say a stop sign, when I accelerate my car wants to stall, if I hold the pedal to the floor it will stall. I have to ease the pedal, or back of to prevent it. However, once underway I can stomp the gas and the car doesn't show any signs of hesitation. I'm not looking for a fast car, just I don't think it should be stalling on me if I stomp it from a red light.
Also, does anyone think that a weak mechanical fuel pump could be delivering too little fuel to the bowl. The accelerator pump was replaced and the carb squirts fine. It seems to stall when if i take a turn too fast, thats why I'm wondering if the carb could be running dry.
I am doing a compression test later when my buddy brings by the gauge. I am hoping its the pump, because the only other thing I can think of is that the previous owner used unleaded fuel and that I may have valve seat recession.
Well, i apologize for the long winded post, but any info or ideas would be so greatly appreciated. Thank you all very much.

That is just how all cars ran fresh from the factory in 1973. "That funny little let-down when you put your foot down... That's what hesitation is all about" The old guys will remember that advertising slogan.

I'm not a carb guy, there is a fix. I read about it here not long ago, but can't locate the thread. Don't worry, someone here will help.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

Royceflo,

The tuning from the factory is very interesting since there was so much pollution control and not very impressive in terms of performance.

The 73 had low initial timing like my 74. The factory calls for 0 degrees. To solve the problem I ended up raising the timing to 5 degrees at first but it would ping now and then when it got hot. To make a long story short all the pollution control came off and I can run 16 degrees of timing now with no pinging. The bog is gone. In fact it is just the opposite. It will put you back in the seat......

Once you are back to a basic and stable motor, a distributor recurve will really make your car perform.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

It sounds like the carb is a little lean. You can jet it up and most 1920 carbs run best with a #58 jet. You can get jets anywhere that has Holley four barrel jets ( same jets that fit you carb).


I few things to check first before rejeting,

1 check for vacuum leaks around the intake where it bolts to head and carb. Also check the intake runners because these intakes can have cracks or casting pit holes sometimes. Use carburator cleaner to spray around on all these parts and if it has a vacuum leak when you spray the piont that is leaking you will hear the engine idle change ( yea do it with the engine running).


2 check the vacuum advane can on the distributor and make sure its not leaking vacuum, and working properly, and that it is hooked up to the carb right.


3 Also make sure the float level in the carb is right, sounds like it may be a little bit low if the fuel pump shows to be working right.



Jess

1973 was the first year for the OSAC valve, which is an emission control device used solely for the purpose of getting the new 1973 cars past the new 1973 Federal emission certification tests so that the cars could legally be offered for first sale. This device is notorious for causing the kind of hesitation you describe. You'll find the OSAC valve on the passenger side of the firewall. There is a hose running to the OSAC valve from the carburetor, and a hose running from the OSAC valve to the distributor vacuum advance. What you want to do is connect the vacuum advance directly to the carburetor. Use the carburetor vacuum port that's presently routed to the OSAC valve, just connect the carb to the distributor and bypass the OSAC valve entirely. If there's nothing else the matter with your engine (the carb is adjusted and working correctly including the accelerator pump, the EGR system is either functioning all the way correctly or is disabled fully, etc.) then this should get rid of your hesitation.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks all, I am going to go through these ridiculous emission controls and poke around to see if your suggestions help. Anyone know what compression I should be looking for with the Comp test? If its 8.4, shouldnt it be around 120psi?

The emission controls aren't all "ridiculous". Don't just disconnect and reroute things willy-nilly. Compression pressure with the engine warmed up, all spark plugs removed, battery fully charged and choke and throttle both fully open should be somewhere between 120 and 140 or so; the most critical thing is that they all be close to each other.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Once you have checked all of the above stuff... you can also slowly work the throttle linkage and check the position of the cam/arm for the acc. pump... we fixed the acc. pump timing on a '73 Holley 1920 recently by moving the linkage rod to the outer hole out of the 3 on the pump cam...

-D.Idiot

I eliminated the OSAC valve and checked for vacuum link at the Distributor can, there was no leak. By eliminating the OSAC, that did fairly drastically change how heavy it bogged. However, if I drop the pedal all the way to the floor it still flat out stalls.
I had adjusted the arm on the Acc. pump during it's rebuild/tune time. I have it placed in the middle hole and that seems to work best for me.
Not to jump ahead of myself either, as getting the current engine to run bug free is my goal at the moment. Does anyone have any opinion on swapping to a super-six manifold set up and the two barrel. I have one kicking around in my garage, I believe it was off a late 70s pick-up. What would be the bonuses and the drawbacks of it. I'm not looking for performance really, mostly I have heard the carbs can be more reliable and that the idle and acceleration are smoother.

How many miles/years, total, are on this carburetor? The 1920 can eventually, after several decades, just come to its end after which a rebuild kit will not help.

Do you get a good, strong shot from the accelerator pump when you open the throttle with the engine off? The accel pump drive spring can take a set after a lot of years; I've cured hesitation such as you describe by stretching this spring to give a firmer push to the accel pump diaphragm.

The Super Six setup works well if the carburetor's in good condition (1bbl or 2bbl, a good carb's better than a bad carb). You'd need the complete kickdown linkage and the shorter throttle cable, too.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks dan, haha, i've been reading other posts...you're all over this forum.

But yes, the acc. pump puts a nice solid shot. I replaced the acc. pump spring with a new one from a carb shop down the road "carbs r us". As far as the mileage on the carb, i can't say as I just picked it up last week, and an older man had it in his garage since 1996. The engine has 38,000 miles, and he has the service papers to prove it, as obviously the car doesn't have a 100k odometer reading.

The carb however looks replaced, as it is far cleaner than the block, yet that doesn't mean a whole lot. Is the super six set up any more reliable than the single, and how is the MPG with a super six. Believe it or not im getting around 20mpg at the moment.

You can get equal or better mileage with a Super Six setup if everything's in good shape.

I still can't help thinking something fixable is out of whack with your carb. How did you (attempt to) clean the main metering block when you rebuilt it?
Have you reviewed previous threads on this kind of hesitation issue here and here ? Did you carefully check the bends and angles of the accelerator pump cam operating link (the bent-heavy-wire link rod that connects the nylon accelerator pump cam to the throttle lever) to make sure all the angles are correct per the FSM specs?

What's the status of the car's EGR system?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.