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Username Post: Carter YF Sluggish above 25-30 MPH today        (Topic#341708)
2ndtime50guy 
Frequent Contributor
Posts: 1320
2ndtime50guy
Loc: Midwestern U.S.A.
Reg: 04-06-12
01-05-17 01:59 PM - Post#2669495    

I have a Carter YF single barrel carb with auto choke. Acceleration got real sluggish and bumpy around 25-30 MPH today, like driving against a fully choked manual choke after it is warm. Auto choke is set where its always been. Is there a chance the accelerator pump diaphram is failing? Or could there be debris in the carb plugging something? This has never happened so I'm stumped.

Two 1950s:
2 Door Styleline Deluxe
4 Door Styleline Deluxe
Read my Profile for a Happy Ending!


Edited by 2ndtime50guy on 01-05-17 02:01 PM. Reason for edit: No reason given.

 

2blu52 
"16th Year" Silver Supporting Member
Posts: 17626
2blu52
Age: 83
Loc: Montana
Reg: 03-12-02
01-05-17 02:24 PM - Post#2669503    
    In response to 2ndtime50guy

What was the temperature today? I had a jeep that I changed to an auto choke, on cool or cold days would run "sluggish" The problem turned out to be heat loss in the tube running from the manifold heat box to the carb. I was necessary for me to wrap the tube with fiber glass insulation to make it work properly.

"PEACE IS THAT GLORIUS MOMENT IN HISTORY WHEN EVERY ONE STANDS AROUND RELOADING"

THOMAS JEFFERSON


 
2ndtime50guy 
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Posts: 1320
2ndtime50guy
Loc: Midwestern U.S.A.
Reg: 04-06-12
01-05-17 03:49 PM - Post#2669518    
    In response to 2blu52

It was 20 with a wind chill of about 10.

Two 1950s:
2 Door Styleline Deluxe
4 Door Styleline Deluxe
Read my Profile for a Happy Ending!


 
Rustchips 
"7th Year" Silver Supporting Member
Posts: 953
Rustchips
Age: 79
Loc: DFW Texas
Reg: 02-24-05
01-05-17 05:47 PM - Post#2669542    
    In response to 2ndtime50guy

You should stay in the house. It's to cold for the car and you.
Cleon

1928 Chevy Coupe
1942 Chevy Sport coupe
1949 Chevy deluxe 4 dr.Fleetline
1954 Chevy Bel Air HTP
1955 Chevy Bel Air HTP
1970 El Camino
1990 F##d Mustang Convertible

Life is like a roll of toilet paper the nearer the end the faster it goes.


 
Bel Air kiwi 
"2nd Year" Silver Supporting Member
Posts: 2303
Bel Air kiwi
Loc: New Zealand
Reg: 04-24-14
01-06-17 12:40 AM - Post#2669583    
    In response to Rustchips

Hi 2nd time, Cleon's probably right. The Below freezing outside air temp was most likely the issue. Although as always it could be any of the usual faults that happen in warm conditions, just happened to happen now.
As you noted in your comment wind chill is a potential factor but in a very specific way in carbs.
The speed and volume of air passing down that carb and mixing with fuel always draws heat out of the carb body. Very basically two things happen, the airflow chills the carb and the energy for the latent heat of vaporization also comes in part from the carb body.
This is not an issue when the inlet air is hot as it doesn't cool so much and it provides some of the energy for fuel vaporization.
But when the air is cold, the carb is the only source of vaporization energy and it can't do it so the fuel stays as droplets and the manifold heat vaporizes some but not all of it. So the mixture is heavy in parts, vapor in other parts and the droplets fall out of the flow in the manifold bends or long runs to the end cylinders.
This is why designing a wet manifold and managing it is as complex as designing an airplane wing. This is also why all carb engines for general road use have some version of intentional manifold heat/energy management. But to make it super broad and super sensitive is expensive, so clumsy and good enough was fine.
When its really cold the problem gets worse as the engine won't get full hot and the thermostat reducing the coolant flow is the only thing that keeps enough heat in the head and manifold to allow it to still run.
But it is running way off and as you noticed it plays up like a red headed foster child.
I would guess that maybe your manifold stove may have seized in the no heat position which would be like having no thermostat as well.
At this level of cold the give away sign is condensation on the carb body, but that is hard to see when you are driving.

If you have seen the programs about Ice Trucking in Alaska and northern Canada you will notice that most if not all of their grille on these big rigs is blocked off with a curtain that intentionally limits airflow across the radiator from very little to nothing. They also have gallons of antifreeze in their cooling system.
This curtain is a mechanism to block the wind chill effect from super-cooling the radiator. If you drive a big rig at 60MPH in those conditions with an open radiator most of the radiator would freeze solid and the engine would boil through lack of flow. Actually the management system would shut it down, but back in the day it would just grenade. If you are fully laded with 40 tons on ice you aren't going so fast so much less windchill and far more engine heat as you are working harder with the weight. So you just peel back one corner of the curtain.



48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars


Edited by Bel Air kiwi on 01-06-17 01:06 AM. Reason for edit: No reason given.

 
Bel Air kiwi 
"2nd Year" Silver Supporting Member
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Bel Air kiwi
Loc: New Zealand
Reg: 04-24-14
01-06-17 01:28 AM - Post#2669584    
    In response to Bel Air kiwi

Ctd. Sorry timed out again.

Anyway the windchill factor matters in two ways in a carb. First if you increase revs you increase the amount of cold air going though the carb but the amount of heat the body can pick up from the engine stays relatively constant. So more revs make for more air chill and more fuel through the bowl cooling it quicker again and both work against the carb using the extra heat the engine is generating as its not getting to the right place and its not happening at a fast enough rate. So revs and rapid throttle change make a bad situation worse. Plus the amount of hot air coming off the back of the radiator will be much less if you are moving along in top gear and this just adds to the issue.

The last phase of this is when we move into super cold air intake temperatures when the air entering the carb does not vaporize any of the fuel droplets and the manifold has almost no effect in helping this. The flow of air drives some of the fuel droplets into the chamber and the combustion chamber pressure rise begins to get the mixture to the sort of condition it should have been in under the carb but there is simply not enough time and the off balance and out of whack mixtures between the favored and poor cylinder means it runs like three valves are burn't two leads crossed and piston holed.


48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars


Edited by Bel Air kiwi on 01-06-17 01:39 AM. Reason for edit: No reason given.

 
2ndtime50guy 
Frequent Contributor
Posts: 1320
2ndtime50guy
Loc: Midwestern U.S.A.
Reg: 04-06-12
01-06-17 04:14 AM - Post#2669591    
    In response to Bel Air kiwi

Thanks for the help! That all makes sense to me. I will have to wrap the tube like 2blu says as this is my only car and I have to get to work. The odd thing is that this is my 2nd winter with this carb set up and it was fine last year. Even colder at times.

Two 1950s:
2 Door Styleline Deluxe
4 Door Styleline Deluxe
Read my Profile for a Happy Ending!


 
carbking 
Senior Member
Posts: 1366
carbking
Loc: Missouri
Reg: 06-14-03
01-06-17 04:39 AM - Post#2669598    
    In response to 2ndtime50guy

A higher relative humidity can also make the issue worse.

Jon

Good carburetion is fuelish hot air!

The most expensive carburetor you will ever buy.....is the incorrect one you attempt to modify!

If you truly believe "one size fits all", trying walking a mile in your spouse's shoes!


 
2ndtime50guy 
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Posts: 1320
2ndtime50guy
Loc: Midwestern U.S.A.
Reg: 04-06-12
01-06-17 05:21 AM - Post#2669604    
    In response to 2ndtime50guy

The car started right up today and I let it warm up for 10 minutes, dialed in the idle mixture screw a little, made sure the heat riser was freely moving, and everything was fine. It got me to work without any stumbling. All I can think is that I didn't let it warm up enough yesterday after work, drove it straight to the gas station, and flooded it as I was starting it to proceed home. The 12 volt heater does seem to drain the battery a bit in the extremely cold weather. Maybe that contributed to the flooding; short drive and a weak spark initially?

Two 1950s:
2 Door Styleline Deluxe
4 Door Styleline Deluxe
Read my Profile for a Happy Ending!


 
2ndtime50guy 
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Posts: 1320
2ndtime50guy
Loc: Midwestern U.S.A.
Reg: 04-06-12
01-06-17 05:37 AM - Post#2669605    
    In response to carbking

Thanks Carb King! Sorry I didn't see your response earlier. It has been a "rainy" winter so far with many ups and downs on the thermometer. Gotta love Indiana...

Two 1950s:
2 Door Styleline Deluxe
4 Door Styleline Deluxe
Read my Profile for a Happy Ending!


 
2ndtime50guy 
Frequent Contributor
Posts: 1320
2ndtime50guy
Loc: Midwestern U.S.A.
Reg: 04-06-12
01-10-17 07:31 PM - Post#2670529    
    In response to 2ndtime50guy

Update: Temps got up to 45-50 this afternoon and it happened again. The car barely made it off the lot at school, so I stopped at the auto shop to get shop teacher's help. I shut off the car to go in and when we returned it was flooded and wouldn't start. We eventually backed all the way off the auto choke and backed way out on the idle screw and it fired right up. I think the carb has gone haywire. Time for a rebuild?

Two 1950s:
2 Door Styleline Deluxe
4 Door Styleline Deluxe
Read my Profile for a Happy Ending!


 
Bel Air kiwi 
"2nd Year" Silver Supporting Member
Posts: 2303
Bel Air kiwi
Loc: New Zealand
Reg: 04-24-14
01-10-17 08:25 PM - Post#2670534    
    In response to 2ndtime50guy

Hi 2nd Time, The only way you end up with the carb flooding the car when not running is the carb truly fuel iced and that melted into the manifold and/or your fuel line pressure overcame the float needle valve. Forcing the fuel into the manifold.
Not the same as flooding when trying to restart.

Battery performance falls with usage and temperature conditions. Unless you recharge as you go the battery works like a tank of energy. Use some and its gone, until you put some more in. Less than about 3/4 of full voltage and the points system falls over. So It won't start.
Available energy changes with temperature. Its not a huge variation but as you get lower it drops and other variables work against you as well such as the volatility of the fuel and the thickness (Viscosity) of the oil, and the energy to vaporizes fuel go up.

Given it didn't happen last year in the same conditions I would guess if you actually have a carb problem, it is most likely to be; dirt, corrosion, or my first pick, a failing needle (Float) valve. It's a wear in service part, so try that first.

Cheers Kiwi

48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars


Edited by Bel Air kiwi on 01-10-17 08:49 PM. Reason for edit: No reason given.

 
2ndtime50guy 
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2ndtime50guy
Loc: Midwestern U.S.A.
Reg: 04-06-12
01-11-17 04:40 AM - Post#2670547    
    In response to Bel Air kiwi

Thanks Kiwi. For what it's worth, the dome lights dimmed when I cranked it this morning and it's back to not starting. I know it's partially due to us adjusting the auto choke last night. We set it with the choke partially opened just to get it started and home last night. It.was fine with a hot engine, but not starting now that it's cold again.

Two 1950s:
2 Door Styleline Deluxe
4 Door Styleline Deluxe
Read my Profile for a Happy Ending!


 
Bel Air kiwi 
"2nd Year" Silver Supporting Member
Posts: 2303
Bel Air kiwi
Loc: New Zealand
Reg: 04-24-14
01-11-17 08:03 PM - Post#2670665    
    In response to 2ndtime50guy

Hi, Charge your battery remotely, Generators take a very very long run to charge a battery while just running. That's why years of research went into developing an alternate solution that can put out more than 50 Amps at low revs and doesn't have a cranky old external voltage regulator. And even they take lots of time to recharge badly discharged batteries. But that is deliberate so they don't overheat and distort the battery plates.
That's what overnight trickle chargers are for.

Cheers Kiwi


48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars


 
2ndtime50guy 
Frequent Contributor
Posts: 1320
2ndtime50guy
Loc: Midwestern U.S.A.
Reg: 04-06-12
01-12-17 12:37 PM - Post#2670781    
    In response to Bel Air kiwi

I don't know if I mentioned; this car is running an alternator. I took the generator and voltage regulator off this summer and installed them on my 1st time '50. I adjusted the timing again last night and the car has started all 5 times I've driven it today without any sluggish acceleration. I'm guessing the timing along with the choke and idle mixture settings caused all this.and it didn't become obvious until the extreme cold and humidity began.

Two 1950s:
2 Door Styleline Deluxe
4 Door Styleline Deluxe
Read my Profile for a Happy Ending!


 
Bel Air kiwi 
"2nd Year" Silver Supporting Member
Posts: 2303
Bel Air kiwi
Loc: New Zealand
Reg: 04-24-14
01-12-17 06:27 PM - Post#2670846    
    In response to 2ndtime50guy

Hi 2ND time, we call that tipping point or the straw that broke the Camels back. What it does tell you is that your servicing schedule needs a re-think if those conditions are going to be a regular thing.
Summer is much kinder on most vehicles than extreme cold. You may even need a fuel additive or change.

Cheers Kiwi

48 3100 RHD, 51 Deluxe 4DR RHD, 51 Bel Air parts car, 52 Bel Air P-Glide LHD. Others 23T, 32 Tudor, 58 Edsel pacer 4DR HDT, 79 F250 351C RHD. 69,70,82 Capri. No mobile, no TV, and no Jap cars


 

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