Carburetor question

[Jon O.]

I just did a rebuild on my carburetor with the help of my grandpa, new float, and needle and seat too. Even after a rebuild, if it sits overnight, I have to pump about 4-6 times before gas gets to it. If I try to start without pumping, it will almost start, until it seems to use up whatever gas was sitting there. It is not flooded. My grandpa said that carbureted cars all start different, and this is just how this one likes to be started. Is this normal?

 

[commando1]

Read up on how to set up your choke properly. Not rocket science but it takes an understanding on how to fiddle with it properly.
On a cold start, you should be able to depress the gas pedal pedal ONCE, and it should start.*

Only AFTER doing that, listen to all the guys yacking away about the ballast resistor...

* Not applicable in ND, MN, ME, and Canada.

 

[FURYGT]

Yes, that can be normal. Try starting it by cranking it with just a bit of pedal. Let us know year & model & engine in your car to be more helpful.

 

[CBODY67]

Carbureted cars will NOT normally start as quick or easy as fuel injected cars, where everything is computer controlled. Some more than others, though.

The Chrysler owner's manual states to depress the accel pedal 1/3 down, then turn the key to engage the starter. This makes sure the automatic choke does it's thing, as needed, and also puts an accel pump shot into the manifold. From there, it might take three engine revolutions for the engine to start.

The automatic choke should close fully at any ambient temp under about 70 degrees F. Then as the engine cranks, the vacuum will activate the "choke pull off" to open the choke so the engine will fire and not be too rich in those first minutes of run time. Holding the throttle at WOT will also manually open the choke valve a bit, too, but should not be necessary unless there is a "flooded" condition.

On these "first thing in the morning" starts, you might check to see if there is accel pump shot available, BEFORE you start the engine. Probably for about three solid shots. If not, then there's something that will need further investigation/attention. The choke valve should also close fully, typically, after the throttle is moved just enough so the fast idle screw clears the fast idle cam. If the choke isn't closing as needed, it might well take 4 jabs of the throttle to put enough richness into the manifold for the engine to fire and run. To compensate for the choke not working as designed.

I'm suspecting the idle mixture and speed were adjusted for best efficient operation? Might pull a spark plug and inspect its condition. #1 or #3 might work best, but which ever one is the easiest to get to is all that matters. If the porcelain is darker charcoal or sooty, then the carb is running too rich, which can hamper quick starting. Might just need to run a spark plug gap gauge through the gap, verifying it in the process, to clean the gap surfaces rather than need new ones, many times. The porcelain should be more of a light tan color with no deposits around it, if things are working correctly.

Make sure the base timing is to spec. The points are in good condition, as are the spark plugs. Some cars start "at the touch of the key", but some others can take a little longer, depending upon the weather temps. Seek to see what works best for your particular vehicle and learn to do it that way every time, for best results. LEARN the car and adapt to what it likes best. Not everything works "by the book", by observation, in all cases.

Of course, what type of vehicle and carb are we dealing with?

Enjoy!
CBODY67

 

[commando1]

I knew it.

 

[CBODY67]

Perhaps I've been in an alternative universe or something. I've never had any issues with a no--start problem caused by the allegedly-evil "ballast resistor". '66 Newport, '70 Monaco, '72 Newport, or '80 Newport. Yet for some people, that seems to be their "go to" solution for no-start issues on Chrysler products. Maybe it's because mine are all 383/400s (except for the 80, which is a 360 2bbl)? Or my cars still have the OEM production pieces on them? The one time I did look at one, there were no cracks kin the ceramic of "evidence of heat" on the resistor itself.

Even when I suspected a "low output" stock coil, the replacements worked as well as the one being replaced, so the new one became "a spare". Never had one leak, either, but I know that happens sometimes.

Just some thoughts,
CBODY67

 

[commando1]

I've never had any issues with a no--start problem caused by the allegedly-evil "ballast resistor".

That was a private joke amongst several of us. Of course, the ballast resistor has nothing to do with it. The entire electrical system has nothing to do with it. Except for the blinker fluid.

 

[CBODY67]

Light blue blinker fluid? Or that container of "blue compression"?

I've heard of the ballast resistor issue for a good while, in other places, too.

Thanks for the clarification.

CBODY67

 

[moper]

It's normal to have to [ump the gas to set the choke. Or to give the cold engine an extra burst of fuel. But - with today's ethanol added fuels - you may need to turn the engine with the starter for 3-4 seconds to get fuel into the carb, then pump the gas twice, then turn the key. It should start and be on "high idle". Within 15-20 seconds tap the gas again and it will drop down some.

If it's well tuned, and not a cold start after sitting, a carbureted car will always start faster than an EFI car. The ECM has to sense the engine is turning - so every EFI car I have ever had or driven of any make, turns 2-3 rotations and then fires. My truck, with it's carbureted 360, will start before the first full revolution is done. Same with my performance cars. Cold starts the EFI will still only need a few rotations to fire. The carbureted if it doesn't have an electric fuel pump will need to turn to pump up fuel...

 

[CBODY67]

In most cases, though, the EFI engine will be more consistent in its starting. Agreed, they need to get computer sensor information for adjustments and such before things settle back down. Some are worse than others, in this respect, by observation. It might take 5 seconds for them to get settled down from a start event. On others, it's sooner. As if the default "start mode" is more dialed-in to start with. If you slam it into gear as soon as it fires, it's not going to act "right", but will if you let it do its thing before you put it into gear. Easy to tell which OEM has the best vehicle computer!

Remembering some of the old car chases where as soon as the engine fires, it's in gear and burning rubber chasing that bad guy. On many newer vehicles, they'd still be sitting there as the bad guy made his SECOND corner in the get-away scene. In more recent times, some diesel-powered emergency vehicles MUST be "settled-down" from their start to take off, so they'll not later stop with a "Check Engine" light, on the side of the road! Spend an extra 30 seconds on the front end of the run rather than not make it at all.

In any event, use the stock carb specs as a starting point from which further finesse might possibly make the final tune a little better, rather than the "absolute best it can be". Be patient and it will tell you what it wants. Maybe 1/8 or 1/16th turn of the idle mixture screws, another 20rpm in the base idle speed, for example. Maybe 2 degrees more base timing? Listen to the engine sounds and how it "feels", for example. If you're just learning, then pay attention to what you're seeing, hearing, and feeling at the factory spec baseline and proceed in small increments. You'll find the optimum setting pretty soon. If the changes make no difference, then go back to the prior setting to verify that it was good to start with.

Enjoy!
CBODY67

 

[Ross Wooldridge]

Make sure your muffler bearings are properly degreed...

 

[PontiacJim]

I just did a rebuild on my carburetor with the help of my grandpa, new float, and needle and seat too. Even after a rebuild, if it sits overnight, I have to pump about 4-6 times before gas gets to it. If I try to start without pumping, it will almost start, until it seems to use up whatever gas was sitting there. It is not flooded. My grandpa said that carbureted cars all start different, and this is just how this one likes to be started. Is this normal?

My '73 Fury starts hard. My brother's 73 Satellite w/360 starts hard.

First, ethanol in the gas does not help as it boils off quicker. Mopars seem to hold heat under the hood once running and when you shut them down, it is quite possible that the fuel vaporizes after sitting long periods.

My brother decided to add an electric fuel pump back at the tank as recommended by the shop who works on his and other older cars. Says it fires right up now. You would normally have to sit and crank it a bit before it would fire up, even after something like running into a store.

With my Fury, it take a lot of cranking to first fire it up when sitting overnight or even months at a time, so I know the fuel has vaporized. When driving around and I stop, it can still take a little doing to get it to fire up quickly. Pumping the gas a couple times can flood it out and it is harder to start, and then I have tried simply holding the foot to the floor which can on occasion produce a nifty little backfire through the carb. It never catches if I just crank the engine and never touch the pedal. So I crank the engine with the gas pedal slightly open to clear any gas which may have built up in the intake manifold. If it does not start on that crank, then I hit the gas pedal once to the floor, let up on it, and then crank. That usually does it. It sounds like the carb is leaking and engine flooding, but there is no evidence of this - so I just deal with it for now and use my starting technique as I don't drive it much anyway.

HOWEVER, keep in mind that there could be other problems causing this. A dirty or plugged gas filter or air filter can add to the problem. Any air leaking into the fuel system, like a cracked or split rubber hose between the tank and fuel pump may not show signs of a leak because it is not pressurized. It can still draw air in, allow the gas in the line to seep out or evaporate, or allow the gas held in by capillary action to trickle out back into the tank.

Check hose clamps to make sure they are tight and not positioned incorrectly or cranked down so tight they crush the hose cutting off fuel supply. Here is my take on some of MY start problems. Went to take my car for a drive, got it fired up, backed into my driveway and then shut it down to pop the hood and give it a once over. For no reason I reached down and grabbed the fuel filter near the fuel pump. When I did, I got a handful of gas, but there was no signs of a leak or smell of gas because it was on the tank side of the fuel pump. Further inspection revealed the hose was loose and the clamp simply spinning around on the hose. I parked the car. Have not tackled the job yet, but figure this was certainly adding to my hot start problem. Will put new ethanol friendly rubber lines on and new filter and see if there is any difference.

Make sure you have a good strong/fully charged battery as well.

 

[Davea Lux]

Also check to be sure the heat riser is not stuck shut, this will overheat the carb and boil out the fuel so the carb is dry the next time you go to start the car, which might explain your hard start issue.

Dave

 

[Big_John]

Read up on how to set up your choke properly. Not rocket science but it takes an understanding on how to fiddle with it properly.
On a cold start, you should be able to depress the gas pedal pedal ONCE, and it should start.*

Only AFTER doing that, listen to all the guys yacking away about the ballast resistor...

* Not applicable in ND, MN, ME, and Canada.

^This^

Only caveat is that the gas may evaporate out of the float bowl after a week or so and then it might be harder to start. YMMV.

 

[FURYGT]

FIW, my yellow 68 Sport Fury with the stock appearing 520" does not have a choke but does have a supplemental electric Holley Blue Pump mounted near the tank that goes to a fuel pressure regulator and then a high volume mechanical fuel pump. Unless the temperature is below 50, with the electric fuel pump that car fires extremely quickly.

Today's gas is horrible and makes our C's harder to start, especially in warm weather.

 

[PontiacJim]

Just to follow up on my car, I finally got around to replacing the fuel filter and rubber gas lines. One of the rubber hoses had the spring type hose clamps and was not doing its job. The hoses were hardened and it looked like the filter had been replaced, but the spring clamp that was used (and often comes with the new filter) was of no use on the hardened rubber and was unable to clamp the hose tightly, so any simply movement of the hose had gas leaking out - or letting air in.

Installed new rubber hoses, fuel filter, and screw type band clamps. Took it for a drive and stopped a couple places. Car started up much better hot without having to crank it several times or play with the gas pedal to get it to kick.

 

[Jon O.]

Just to follow up on my car, I finally got around to replacing the fuel filter and rubber gas lines. One of the rubber hoses had the spring type hose clamps and was not doing its job. The hoses were hardened and it looked like the filter had been replaced, but the spring clamp that was used (and often comes with the new filter) was of no use on the hardened rubber and was unable to clamp the hose tightly, so any simply movement of the hose had gas leaking out - or letting air in.

Installed new rubber hoses, fuel filter, and screw type band clamps. Took it for a drive and stopped a couple places. Car started up much better hot without having to crank it several times or play with the gas pedal to get it to kick.

Thanks, I have those clamp type too, I may look into that.

 

[CBODY67]

In addition to the clamp style, placement is also important. I'd always suspected it might be, but I found a GM tech publication which graphically illustrated how it should be for best results. And it might also explain why the wire clamps tended to work as good as they did.

On the metal tube, there is usually an expanded-diameter area near its end. The hose is pushed over that area with the clamp being placed behind that area. Where, behind that area, is where the level of execution can be important.

If the hose is pushed well past about an inch behind the tube's larger diameter, the clamp is placed near the end of the rubber hose, it might provide a "double seal" of sorts. Once where the hose goes over the larger diameter area and the second one where the clamp is placed. As fluid can possibly get past that larger diameter area, then "pool" between there and the clamp's location, this wasn't considered "optimal".

If the clamp is placed onto the hose at the "bump" from the larger diameter area, then the sealing area is more intense and also minimized in sealing area. Not as good as it might look, especially with a wire clamp and less so with the worm-drive band clamp.

The optimal location of the hose is it being long enough to go about 1 inch past the tube's expanded diameter area. The clamp placement is just behind that "bump" in the hose. This can maximize the clamping/sealing area of the clamp against that expanded diameter area of the tube. Keeping any pooling of the fluid to a minimum, if it happens, too.

The spring wire clamp's diameter can match the contour of the tube better than a band clamp might, on the backside of "the hump in the hose", for a more consistent clamping amount in the desired area.

I know we've all seen the slots in a worm-drive band clamp eat into the rubber hose it's around, sometimes flaring the end of the rubber hose outward at its unclamped end. Too much torque, all in the name of "no leaks desired". On the assembly line, variability of installation has to be diminished or eliminated. One way was the "slide it on, in the designated spot" spring wire hose clamps. How the worm-drive hose clamps might be tightened or not tightened can be very variable, sometimes resulting in "re-checks" as the vehicle's "Final Check" is done at the assembly plant or possibly a situation corrected before the customer receives the car, by the dealer or somebody else. The worm-drive clamps could be specified in certain areas for "fleet sale" vehicles, I believe, where ultimate reliability was needed/desired. I also recall that when hose service was needed, the spring wire clamps were usually replaced with the stainless steel worm-drive clamps. As that repair station was usually concerned with "come backs", they made sure the clamp tightness was adequate before the vehicle left the shop bay.

In the middle 1980s, Chevrolet used some black worm-drive hose clamps on some of their 5.0L engines. When I saw them, I looked for the particular part number and ordered some, but they came in silver rather than black.

As an aside, one of our Mopar club members demonstrated how applying "gun blue" compound to common hardware store bolt heads would emulate the "90-hour salt water corrosion resistant" black coating on many OEM body bolts used by Chrysler and others. We wouldn't have believed it, otherwise! He just stumbled upon it one night while watching television. Pretty neat! It might have "the look and texture", but not the real protection? Have to make sure the bolt hardness and "shape of the head" (i.e., flange head) is correct for the application!

Enjoy!
CBODY67