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Discussion Starter · #1 ·
I need your help with what I can only assume is either a carb or timing issue. Trouble is, I have no clue how to troubleshoot or fix it. So can you guys help?

Here's what's goin on: First time I start the Caddy each day, I have to either crank for all eternity, which I don't like doing, or shoot some starter fluid down the carb. It runs rough at first, then, after it warms up for 2 or 3 minutes, it idles nice & smooth. Any throttle at all & it bogs down, I've got to give it a very delicate touch to pull off the line, and if I do it wrong I stall out in the intersection, but as soon as it gets movin', she runs smooth & powerful. Well, except at the shift from 2-3, it bogs down again & I have to let up on the throttle 'til it catches up to itself. The motor is bone stock '55 331 with stock carb & ignition & everything, only notable change is an electric fuel pump instead of the mechanical stocker. So, where do I start? How do I fix it?
 

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Bill-E-BoB said:
no clue, the previous owner put the electric fuel pump in.
where it located ?
near tank or up front ? either knocking life span on motor .
try a gas tank from a mower say and hang it up high and gravity feed carb .
any better ?
try the old crayon on the exhaust ports and see if all melt same .
i had a carb jet clog on one side and it ran as you describe on 4 cylinders only .

that pump needs to be near tank .
they better pushers than the long draw straw .
 

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Question

I take it the car has run without problems in this configuration so far and that this is a new problem.
I think that you may have carb issues. Have you tried turning on the car and waiting some time to see if the pump will fill the carb with fuel before starting.
Have you ever had the carb apart, I wonder if the float may be stuck in the carb as to not let fuel in the the carb correctly.
Also if your primaries jet is clogged it will give you these issues.

Vic
 

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Bill-E-BoB said:
I need your help with what I can only assume is either a carb or timing issue. Trouble is, I have no clue how to troubleshoot or fix it. So can you guys help?

Here's what's goin on: First time I start the Caddy each day, I have to either crank for all eternity, which I don't like doing, or shoot some starter fluid down the carb. It runs rough at first, then, after it warms up for 2 or 3 minutes, it idles nice & smooth. Any throttle at all & it bogs down, I've got to give it a very delicate touch to pull off the line, and if I do it wrong I stall out in the intersection, but as soon as it gets movin', she runs smooth & powerful. Well, except at the shift from 2-3, it bogs down again & I have to let up on the throttle 'til it catches up to itself. The motor is bone stock '55 331 with stock carb & ignition & everything, only notable change is an electric fuel pump instead of the mechanical stocker. So, where do I start? How do I fix it?
sounds like a bad accelerator pump in the carb. every time you hit the gas for acceration, it needs to have the pump shot so the engine doesnt bog... same reaon it wont start, the nozzles arent getting any discharge to give the engine any fuel. time to rebuild the carb
 

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Discussion Starter · #7 ·
Vic, good call on waiting for the pump to feed fuel through to the carb. I turned it on, let the pump run for about 45 seconds, gave the gas pedal a couple pumps & it started up as easy as when I use starter fluid...makes perfect sense too now that I think about it.

I'm headed to the parts store now to see about a rebuild kit...that'll include an accelerator pump right? I'll let y'all know how it goes.

Thanks!
 

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Discussion Starter · #8 ·
So last night my carb rebuild kit finally came in (good lord its harder to find parts for a '55 Caddy than a '69 Camaro, in case anyone is curious) & I rebuilt the carb & put it back on. Got everything back together & fired her up, and the strangest thing happened. I stepped on the gas pedal, & the engine revved! :thumbup: Looks like that did the trick!

I can't be 100% sure yet because dummy me managed to poke a hose clamp through the fuel line so it sprayed gas all over the engine compartment & I had to shut it off right away, but I'll grab a new hose on the way home from work today & should be good to go.
 

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Discussion Starter · #9 ·
Hmm, its MUCH better...but still bogs sometimes if I get on it real hard. So I'm guessing I just need to adjust it right? So, how do I do that? So far, I started with the mixture screws at 2 full turns out...wouldn't start, brought 'em out 2.5 & it'd start but idled crappy & stalled, brought 'em out to 3 & it started & ran but rough...brought it to 3.5 & it ran nice & smooth. Took it out for a drive around the neighborhood, and under normal acceleration its got a very very slight hesitation for a second, then went fine. Under hard acceleration, like jumping on full throttle from a stand still, it bogs down, almost dies, then picks up & runs strong.

There's another adjustment screw I don't remember seeing on any other carburetor by the way, its a big ol' flathead screw on the throttle body kind of hidden behind the throttle linkages on the drivers side. I kept track of how many turns it took to remove it & screwed it back in the same number of turns when I reassembled...but I have no clue what its doing or how it should be adjusted.

So...whats my next step?
 

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One question, when you rebuilt the carb did you clean all of the jets out, it sounds like your primary is plugged up. that is why you had to turn out your mixture screws so far. I would check that. It is always best once you get the car to run to adjust the screws while it is running turn them in until it just starts to stumble then back it out a little bit. It is a balancing act between to lean and to rich.

Vic
 
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