Carb Spacer for a 200 1 barrel ?????

[Anonymous]

Make sure your throttle plates are closed completely. If they are not, the adjustment of the fuel mixture screw can produce inconsistent results. It might also explain why the screw is backing so far out, and why it is able to handle a richer mixture.
Doug

 

[Anonymous]

The throttle plate clearance...never thought of that... is it something I can adjust or is it fixed?

How much clearance is about normal looking down into the throat of the carb. I've heard about using a drill bit (without dropping it of course) to measure the gap.

Is that a valid technique?

Thanks,
Steve-O

 

[addo]

The other thing worth a look is that the auto choke feed (if it has one) is not letting exhaust into the carb.

 

[Lazy JW]

Steve-O,
Sorry about the delay in responding. This is haying season here and I haven't been able to get to the post office during business hours. I do still have the micarta if anyone is interested and not in too much of a hurry. Welcome home from the cruise
Joe

 

[Anonymous]

The drill bit exercise is used to set the choke plate. You want to make sure that the throttle plate at the base of the carb is closed. Adjust the throttle plate with the idle speed screw which bottoms out on a lever connected to the throttle plate shaft.
Doug

 

[Anonymous]

Lazy JW...no worries. I get pretty busy getting underway and all. Hay season sounds like a back buster to me. If you get a few pieces of micarta to spare (say 3"x5" in size)...let me know what I can put in the mail to you...

Doug,
I will check the lower throttle plate today by visually looking down the carb throat...and let you know how it helps.

I still need to fab reflective heat shields for either side of the carb over the intake manifolds.

Cheers,
Steve-O

 

[Anonymous]

Checked the lower throttle plate and it seals up real nicely when at normal idle position....hmmmmm

Will keep you updated on this I'm sure carb heat soaking is an issue more than I am experiencieng

Cheers,
Steve-O

 

[Anonymous]

A couple of dumb questions on heat choke....

Should hot exhaust gasses actually flow through the tube?

Or should the tube simply heat up and transfer conductive heat to the choke spring?

Steve-O

 

[CoupeBoy]

If you have the original carb on the car still the choke warming tube should go all the way through the exhaust manifold and should get warm from sucking air, but NOT have exhaust fumes running through it. Those tubes are known to rust through and leak exhaust into the line, which *could* be bad.

-ron

 

[CZLN6]

Howdy Steve-O and All:

Ron hit on a good possibility. Check to make sure that no exhaust is coming to the carb choke. If it is this will make the carb choke and idle system work very poorly very quickly. Look for exhaust contamination inside the choke bimetal spring housing. Even at it's best this was not one of FoMoCo's better ideas. New, the heat transfer tube drew unfiltered air, through the cast in tube in the exhaust manifold to heat it, into the choke housing by engine vacuum. Why they would draw unfiltered air directly into the carb is a mystery. It is not unusual, over time for the exhaust manifold to deterioriate/crack or otherwise degrade itself to allow exhaust to be sucked into the carb. The other possibility is for the hole through the exhaust manifold to become plugged. either could be part of your porblem. It is worthwhile to check this out.

I am also still concerned about your A/F ratio at idle. If the idle circuit is too lean it will generate more heat than usual at an idle. Your description of the way the low speed air screw was working is a great big question mark. How long has it been since you've rebuilt this carb. It may benefit from a good internal cleaning. I have very little experience with the Holley #1940, but know that all FoMoCo carbs are susceptible to dirt and wear. In the mean time, set the idle to the highest vacuum reading. You should be able to find a longer tension spring at the junk yard. Be sure to reduce the idle speed each time it goes up.

I know you said that you have checked the timing, but retarded ignition setting will generate more heat too. You might want to recheck it, and even try an increase initial advance setting.

I know you are committed to the heat transfer barrier solution, but I can't help going back to basics. If all is working as it should the additional heat barrier should help performance, not solve a problem.

Keep us posted.

Adios, David

 

[Anonymous]

David,
Great ideas. I will try them all and get back to post my results.
It may be a week or two as I, SWMBO (she who must be obeyed) and the kids are on vacation and out of the state for a couple of weeks.
Cheers and thanks to all.
Steve-O

 

[MustangSix]

Good stuff, and often free for the asking is a scrap piece of Corian countertop material. It is easy to work, heat resistant, fuel resistant, and you can tap it for the carb studs. Just stop by a building construction site, especially for upper end houses, and ask for a scrap from the sink installation.

 

[addo]

Anyone who builds vanities will have oval shaped centre cutouts. Don't breathe the dust. (Another nail in my coffin was spending a day cutting this stuff into 1/8" strips and machine sanding it!) I've also made Corian kitchen chopping boards from those oval cutouts.

 

[Anonymous]

I was busy rerouting the heater core coolant line from through the carb spacer to around the carb spacer. Clearly it was hot enough as it was to avoid carb icing.

A prior owner had installed a coolant flush line in the hose. You know the kind where a garden hose connects up? Well as I removed one end of the hose fromit I notced something stuck in the plastic T...a chunk of metal about the size of kidney bean was wedged in there. I had to get some small needlenose to pull it out. It ispossible this lack of circulation through the hose contributed to my carb overtemp.

So after reroutingthehoses, off I went on atest drive. I checked temps of all hoses with an IR thermometer and they were all around 180-185 while runing and idling. The carb never went over about 120 degrees. Which I'd expect due to underhood heat buildup.

Anyways...I may have found the problem. I'm rebuilding an 1100 autolite to have as a spare andmay tinker with that, too.

Will keep you all posted on any thng new I find orproblems I encounter.
Cheers,
Steve-O

 

[Anonymous]

I know this is an old post, but....

As I removed my exhaust manifold to install my headers last week, I noticed it looked like the exhaust manifold gasket was leaking above the 3/4 cylinder exhaust port. Scorcing witness marks would put hot gasses impinging on the bottom of the carb.

That could have been my problem all along.

Cheers,
Steve-O

 

[Anonymous]

I would also suggest finding a way to get your inlet air from somewhere farther from the exhaust manifold. The stock air cleaner on my wagon has "front" stamped on it which puts the air horn over the distributor in effect getting intake air from the cooler side on the engine compartment.
The cooler the intake air the better it will run--right up untill you get iceing. This is why "ram air" works so good--probally from the cooler outside air more than the "ram" effect. Also why new vehicles source their intake air the complicated way they do. Lean fuel and hot air works really poorly. You are probally dealing with a lot of little things which when combined add up to your problem. That exhaust leak was being sucked right up to your intake both heating your carb body on the way by and your carb throat on the way down especially at lights when the air flow past the engine is minimal.